tag:blogger.com,1999:blog-88602299201222506052024-03-19T01:48:50.137-07:00Jim's CLEO BlogNews, notes, ideas, and observations on CLEO: 2013 in San Jose, CA, USA.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.comBlogger52125tag:blogger.com,1999:blog-8860229920122250605.post-67326177302302883512013-06-13T11:35:00.004-07:002013-06-13T11:35:54.086-07:00<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
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<tr><td class="tr-caption" style="text-align: center;">Compound eye fabricated by Song et al. Photo from UIUC College of Engineering</td></tr>
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Browsing the post deadline papers, whose sessions will run from 8:00-10:00 pm this evening, it seemed the Applications and Technology session exhibited a zoological theme.<br />
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<strong>Fly in the Ointment:</strong><br />
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In postdeadline paper ATh5A.5, to begin at 8:48 pm, Song et al. will present work recently published in <a href="http://www.nature.com/nature/journal/v497/n7447/full/nature12083.html"><em>Nature</em> </a>on compound eye cameras that mimic the physiology of a fly's eye. Unlike human eyes or the eyes of other vertebrates, most animals use compound eyes that have many optical units (facets), each with their own lenses and set of photoreceptors. Though compound eyes lack the sensitivity and resolution of single-lens eyes which work by forming images on a detection plane, they can have infinite depth-of-field without the need to adjust the focal length of any of the lenses. Because of this, compound eyes are very adept at calculating/perceiving relative motion. A good set of compound eyes allows the fly high-precision navigation while in flight. Digital compound eyes therefore show great promise for micro air vehicles (MAVs) to be used for reconnaissance, sensing, and diagnostics in tight spaces (say locating people in a collapsed building, or flying inside and around machinery and other cramped environments with extreme conditions: high radioactivity, temperatures, etc).<br />
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What makes Song et al.'s work, a multi-institutional collaboration lead by the Beckman Institute of University of Illinois Urbana-Champaign, so compelling is that they make use of recent advances in stretchable electronics and hemispherical detector arrays to create a compact, monolithic, scalable compound eye.
Essentially, the collaboration fabricated a planar layer of elastomeric microlenses and a planar layer of flexible photodiodes and blocking diodes that are aligned and stretched into a hemispherical shape. Serpentine-shaped metal interconnections on the electronics aid in flexibility.
The Beckman Institute collaboration achieved near infinite depth-of-field and 160 degree field-of-view.<br />
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<strong>Crocodile Smile:</strong><br />
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Postdeadline paper ATh5A.3, to begin at 8:12 pm, from Yang et al. of Case Western Reserve University actually addresses clinical diagnostics of <em>human</em> tooth decay using Raman imaging, though they image an alligator tooth to help demonstrate proof-of-concept (note all alligators are crocodiles so the cute colloquialism above is technically correct, albeit it is reaching a bit!).<br />
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Current clinical practices for dental caries (decay) lack early-stage detection. Late-stage cavities often require multiple fillings or more costly measures such as crowns, bridges, or even entire replacement of the tooth over the tooth lifetime because of the insufficiencies of x-ray and visual observation to detect lesions.<br />
If tooth lesions could be detected early, they could be remineralized at an early stage of decay, thereby preventing future costly, invasive procedures.
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Yang et al. use global Raman imaging that implements a 2D-CCD array and images at a single wavenumber over full-field of view rather than point inspection over a spectrum of wavenumbers. Their Raman images show a clear border between the dentin and enamel of an alligator tooth, showing high contrast in mineral signal intensity. They also show similar images for human teeth indicating their technique shows good promise for early clinical detection of tooth decay.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-27700575736082024492013-06-12T10:04:00.002-07:002013-06-12T15:56:09.668-07:00Laser Fusion for Sustainable Energy<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://www.llnl.gov/news/aroundthelab/2011/Mar/images/nif_target-chamber_big.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="308" src="https://www.llnl.gov/news/aroundthelab/2011/Mar/images/nif_target-chamber_big.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><em>View from inside the target chamber at NIF showing the pencil-shaped target positioner. Image from </em><a data-mce-href="https://www.llnl.gov/news/aroundthelab/2011/Mar/ATL-040111_physics-today.html" href="https://www.llnl.gov/news/aroundthelab/2011/Mar/ATL-040111_physics-today.html"><em>LLNL</em></a></td></tr>
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Yesterday began two days of laser-driven fusion talks punctuated by a visit to the nearby National Ignition Facilitiy (NIF) at Lawrence Livermore National Lab (LLNL) as part of CLEO Applications and Technology Special Symposium: The Path to Sustainable Energy: Laser Driven Inertial Fusion Energy.</div>
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The session began with The Physics of Laser Driven Inertial Confinement Fusion (ICF) and continued with the Technology of ICF Drive Lasers and Laser Facilities, and Optical and Nuclear Diagnostics. After the tour of NIF today, the symposium will pick up again on Thursday culminating in Future Perspective of ICF as Sustainable Energy Source.</div>
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<a href="https://lasers.llnl.gov/programs/nic/icf/">A tutorial on ICF</a> on the NIF website gives a cute recipe for creating the temperatures and pressures needed for fusion on earth that are only found elsewhere in our universe in stars,</div>
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Recipe for a Star:</div>
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- Take a hollow, spherical plastic capsule about two millimeters in diameter (about the size of a small pea)</div>
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- Fill it with 150 micrograms (less than one-millionth of a pound) of a mixture of deuterium and tritium</div>
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-Take a laser that for about 20 billionths of a second can generate 500 trillion Watts</div>
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-Wait ten billionths of a second</div>
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-Result: one miniature star</div>
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<tr><td class="tr-caption" style="text-align: center;"><em>Figure of the hohlraum and a cross-sectional view (right) showing the fuel capsule. Figure from </em><a data-mce-href="https://lasers.llnl.gov/programs/nic/icf/" href="https://lasers.llnl.gov/programs/nic/icf/"><em>LLNL</em></a></td></tr>
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Of course the devil is always in the details. Ignition, in which more energy is generated from the reaction than went into creating it, has yet to be achieved. In 2009, NIF reached its laser energy goal and thought ignition would be achieved by fall of 2012.</div>
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John Lindl, of LLNL began today's session speaking about many of these devilish details, particularly on NIF. For example, besides having the necessary peak power, the 20 ns, 500 TW laser needs to have the proper pulse shape, which is a strangely-shaped series of four pulses of tailored delay and power in order to deliver four shocks to the target at the proper intervals. </div>
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The target capsule, which may seem to be a trivial piece of the puzzle, has undergone an intense 20- year effort. Different shells of ablator materials, size, shape, density, concentricity, and surface smoothness are all key factors in a symmetric collapse (the attempt to get the correct "spherical rocket"). Lindl, spent a good portion of his talk showing diagnostics images of the collapse, and efforts to optimize the system to better ensure symmetric spherical collapse and confinement. </div>
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Other factors include whether to use direct drive (hitting the capsule directly with the many laser beams) or indirect drive (hitting a cavity called a hohlraum with the beams to generate a symmetric barrage of x-rays to initiate collapse). NIF uses a hohlraum and 192 beams. Omega in Rochester, NY uses direct drive, which accelerates more fuel to burn, potentially for better energy production (when that day comes). Beam configurations, target placement and position, and much more come into play.</div>
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Of course simulation has been a key factor in design, result interpretation, and future direction. The immense effort for ICF at NIF, as well as other the facilities in the U.S. and around the world are extremely impressive and the problems are complicated, beautiful, and rich.</div>
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<a href="https://lasers.llnl.gov/about/missions/energy_for_the_future/life/">Laser inertial fusion energy</a> (LIFE) is a worthy goal which could deliver a sustainable carbon-free energy source. There is no enrichment, no radioactive waste, and no worries of a meltdown; unlike fission chain reactions, when you turn "off" fusion, it is "off". NIF is an experimental facility made to understand the physics and technology necessary for LIFE and not scalable to a power plant. Scaling ignition towards operable power plants is another direction of physics, engineering, and optics research.</div>
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<tr><td class="tr-caption" style="text-align: center;"><em>Schematic of how laser ignition fusion may interface with a power plant to deliver a sustainble source of electricity. Image from</em> <a data-mce-href="https://lasers.llnl.gov/programs/ife/how_ife_works.php" href="https://lasers.llnl.gov/programs/ife/how_ife_works.php">LLNL</a></td></tr>
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Currently, targets are fixed and the laser delivers a few shots a day so that experiments can be changed out, realigned, and optics and components can cool down. In a power plant facility, the hope is to use a higher-repetition rate laser to deliver 20 shots a second. Targets would be injected at speeds of greater than 100 m/s to continually burn fuel, which would heat up a low-activiation coolant of lithium-bearing liquid metals or molten salts surrounding the target in order to convert water to steam with which to turn a turbine.</div>
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Lindl said that NIF is just 2 to 3 times away from achieving ignition, meaning the output energy from the fusion reaction is one-third to one-half of the input photon energy from the laser. Though nature has provided some delays from what was previously thought, ignition is realistically around the corner. Laser ignition fusion power plants may be close as 2030.</div>
Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-77384704850115077422013-04-21T20:21:00.002-07:002013-04-24T14:31:42.026-07:00New Trends in Fiber and Fiber Applications<br />
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Top: Microplasma ignition in an argon-filled kagome-latticed</div>
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hollow-core photonic crystal fiber. Bottom: scanning electron </div>
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micrograph of fiber facet, from B. Dabord et al, CLEO 2013 </div>
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talk, <span style="text-align: start;">CTu3K.6, "Microconfinement of microwave plasma in </span></div>
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photonic structures." Microplasmas show promise for </div>
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applications requiring small confinement of short-wavelength </div>
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visible or UV light such as photolithography or compact </div>
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UV laser emission sources.</div>
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Microwave plasmas, optical vortices, gravitational wave detection, and mode-division multiplexing for high-capacity telecom systems are just some of the topics in <a href="http://www.cleoconference.org/home/submit-papers/topic-categories.aspx#si11">CLEO Science and Innovations 11: Fiber, Fiber Amplifiers, Lasers and Devices</a>. I recently had an opportunity to speak with subcommittee chair, <a href="http://www.bu.edu/ece/people/faculty/o-z/siddharth-ramachandran/">Siddharth Ramachandran</a> from Boston University, U.S.A. to discuss this year’s program on fundamental fiber technology and devices. Though at a surface glance we may think fiber and fiber applications to be very conventional or already “all-figured out”, Ramachandran noted the fact that this subcommittee continues to receive so many submissions year-after-year (in fact the second largest in the entire conference for 2013) indicates that this is still an extremely active area of fundamental and applied research. <br />
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Ramachandran said that contributed and invited talks for the subcommittee could be divided into to two main categories: 1) Novel Fiber, and 2) Fiber Applications. The latter represents breakthroughs in engineering, instrumentation, and devices from fiber technology introduced five to fifteen years ago. It is the product of well-tended ideas, hard work, and ingenuity coming into fruition. The former, on the other hand, will likely be the seeds for cutting-edge instruments and systems five to fifteen CLEOs from now. In terms of novel fiber work, Ramachandran discussed two trends 1) Kagome-lattice structures, and 2) Mode-division multiplexing for high-capacity communications.<br />
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“We are still developing all sorts of novel fibers. What a fiber is, in terms of being a high-index region that guides light surrounded by a low-index region, is not a settled issue. There are actually a lot of innovations going on.”<br />
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Ramachandran spoke of how a decade back, the excitement in fiber research centered around photonic band gap fiber (PBG) which guides light in air (or a structure of silica/air-cores), but still provides many of the properties of standard single-mode fiber, particularly confinement and guidance over many kilometers of length. “That was very exciting, and then what happened afterwards is people found out these band-gap effects are nice for guiding light but they tend to have very small spectral regions where they can guide light, so it is not as universal as our old fibers.”<br />
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Kagome-lattice fibers, named for the trihexagonal pattern of air-holes resembling the weave-pattern of a Japanese Kagome basket, may provide one solution to having the versatility of air-guided fibers, while allowing large-bandwidth propagation.<br />
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“What Kagome lattice fibers essentially do is solve this spectrum-limiting problem we had with photonic band-gap fibers. You can get huge bandwidth out of these, albeit with slightly higher (theoretical) losses. And so they have been very interesting for doing nonlinear optics of gasses filled in these fibers, to do all sorts of dispersive applications where you need crazy high-bandwidth, and for instance to create plasmas. And then there are people who are trying to make ignition torches with fibers which one would never have thought of doing maybe even five years ago,” said Ramachandran.<br />
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Left: Spiral interference pattern of twelve distinct orbital angular momentum<br />
states (vortex modes)after propagating through 2 m of the air-core fiber shown<br />
on the right. Right: photo of the facet of the core shown on top and index profile</div>
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on the bottom. From P. Gregg et al, CLEO 2013 talk CTu2K.2, "Stable Transmission</div>
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of 12 OAM States in Air-Core fiber." The potential for simultaneous propagation<br />
of so many modes shows promise for mode-division multiplexing for high capacity<br />
telecom systems.</div>
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The other category for submissions on novel fiber development on this subcommittee has centered on mode-division multiplexing for high-capacity telecom systems. Ramachandran discussed,<br />
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“The simplest way to scale information capacity might be to not just use a single mode in a fiber, but to start using multiple modes. And that brings with it a lot of complexities of how different modes interact with each other and what impact dispersion has? What does the area of the fiber do, etcetera, etcetera? Which cycles back to being a fiber design and fiber fabrication problem. So there is a lot of innovation going on there. Even figuring out what modes one wants to send. Are they the standard modes that we have seen in textbooks? Or are they these more exotic orbital angular momentum or vortex modes?”<br />
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Top: Areal view of the Laser Intereferometer Gravitational-Wave</div>
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Observatory (LIGO) at the Hanford Observatory site showing</div>
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one of the 4 km arms. Photo from www.ligo.org image library. </div>
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Bottom: One of the possible 3rd generation fiber-amplified laser</div>
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sources for gravitational wave detection designed by Quest Centre</div>
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for Quantum Engineering and Space-Time Research and Laser </div>
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Zentrum Hannover e.V. Photo from Thomas Damm, Quest. Peter </div>
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Wessels from Laser Zentrum Hannover e.V. will be describing </div>
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many of the stringent requirements of laser sources used for </div>
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gravitational wave detection such as high average power </div>
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(~100 W to kW), single-frequency emission, ultra-low amplitude </div>
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and phase noise, and diffraction-limited beam quality in</div>
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CLEO 2013, invited talk, CW3M.5, "Single Frequency Laser </div>
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Sources for Gravitational Wave detection." </div>
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In addition to contributed submissions in these areas, four of the invited talks concern novel fibers and their propagation effects. On the other hand, the remaining invited talks, tutorial, and contributed submissions focus on fiber applications. The tutorial, by Michael Marhic of Swansea University, U.K. entitled <a href="http://www.cleoconference.org/home/program/invited-speakers/#ScienceInnovations">“Fiber Optical Parametric Amplifiers in Optical communications,”</a> will be given on Thursday June 13, from 2:00-3:00 pm. The invited talks in fiber applications, which are indicative of the contributed submissions, comprise topics as diverse as fiber parametric devices, microwave plasmas, gravitational wave detection, mid-IR sensing, and ultrafast laser combs.<br />
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Ramachandran notes, “And the interesting thing about that space is the fiber itself that people are using is perhaps something that was developed anywhere between five years ago to maybe even fifteen years ago. We are now beginning to see all the promise that we initially thought that fibers could deliver and actually seeing applications across different disciplines of science and technology.”<br />
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Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-64604262347138481222012-12-24T22:56:00.000-08:002012-12-24T22:59:06.610-08:00Optics for Peace of Mind<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXSduXNk5x7dae63kX4wzIJFOfjq59Ud0wZazCRMIDgHbZ91Cme6QK3Cmpm7XmBzyGY5UlA0qWFs7xSS9I28RuUQnuGSCznT6DUdKzL6mq70D_w69nXIjZO_Kjk4ZOGIcrP9HK9KPo7Es/s1600/Picture1.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="261" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXSduXNk5x7dae63kX4wzIJFOfjq59Ud0wZazCRMIDgHbZ91Cme6QK3Cmpm7XmBzyGY5UlA0qWFs7xSS9I28RuUQnuGSCznT6DUdKzL6mq70D_w69nXIjZO_Kjk4ZOGIcrP9HK9KPo7Es/s400/Picture1.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Demonstration of phase gradient microscopy in thick-tissue with back-illumination<br />
suitable for endoscopic integration. (a,c,e) amplitude images (b,d,f) phase gradient<br />
images of mouse intestinal epithelium. From T. ford, J. Chu, and J. Mertz, Nature <br />
Methods, 9, 1195 (2012). Jerome Mertz, Boston Univeristy, among other biomedical<br />
researchers, will be presenting latest breakthroughs in endoscopic imaging during<br />
invited talks at CLEO 2013 Applications and Technology: Biomedical.</td></tr>
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In the last two months, I gained a much larger appreciation for optical technology. Abdominal pain and pressure sent me to a number of doctors’ visits and a handful of endoscopic procedures: an upper-GI endoscopy, a colonoscopy, and a capsule endoscopy (the video camera in a pill). Before these, the most serious medical procedure I had was a setting of a broken arm from a failed skateboarding trick when I was 11 years old. The stomach pain frightened me. It was deep inside where I couldn’t see it or get at it and it was making daily tasks and living difficult. I was so relieved to be prescribed the first endoscopy and then the followup procedures. It gave me an element of control. The thought repeatedly running through my head before and after these procedures was, “how fortunate I am to live in the time I am in.” The upper-GI procedure took less than 15 minutes, was painless, and I found out immediately after that my esophagus and stomach looked healthy. Tests from biopsies less than a week later confirmed this was true. I had similar experiences with the other endoscopies. I was given amazing information about by internal organs in fairly non-invasive short outpatient visits. The figure below shows one of the video frames of my stomach.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKkolke92pg6irNfUoDzP2Xi1vYHUrsJUzCv7R3PufUXFhoD-r2dhhQX1UeDPdtsmmfdeK8Y4957XsAjOWhiMNDX33XfPiZC6NaTGXdg92wQr_coDmN6tY1H9QehQL8CKDLEeAiubf6YY/s1600/GIJVH_0005.tif" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKkolke92pg6irNfUoDzP2Xi1vYHUrsJUzCv7R3PufUXFhoD-r2dhhQX1UeDPdtsmmfdeK8Y4957XsAjOWhiMNDX33XfPiZC6NaTGXdg92wQr_coDmN6tY1H9QehQL8CKDLEeAiubf6YY/s320/GIJVH_0005.tif" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Stomach tissue from my own recent upper GI endoscopy using <br />
a conventional commercial endoscope.</td></tr>
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Because my own work in ultrafast laser systems has applications in nonlinear endoscopic imaging, I have used the words “optical biopsy” (the idea that tissue is cleverly analyzed with photons during the procedure instead of "barbarically" exised to be sent to a lab and analyzed later) and “non-invasive” in introductions to papers, talks, or in explanations to lab visitors how an ultrafast laser has relevance to the average person. In the promotion of ultrafast lasers for optical biopsy, I have sometimes talked about how the time and effort it takes to run biopsied tissue through histology is long and arduous-it needs to be sliced thin and stained in order to be viewed with a conventional microscope, and then analyzed by an expert. The patient distressingly waits for a diagnosis and also pays a non-trivial sum of money for the professional time involved for analysis.<br />
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I couldn’t have imagined the importance of these motivations before my own endoscopic procedures. What was part of my ultrafast laser stump speech was suddenly very real and worthy. My own experiences were definitely non-invasive. What would have been my options when endoscopes were larger and bulkier? What would have been my options prior to widespread use of endoscopic diagnosis? And though my waiting for histology was short, it was still difficult and definitely costly. What advantages will the next generations have as optical researchers and engineers push endoscopes to use more imaging modalities? Push them to smaller sizes and with more functionality? What peace of mind can we pass on?<br />
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No doubt many contributed talks to CLEO 2013 and postdeadline papers will address advances in endoscopic procedures, endoscopes, and catheter-based probes. Last year’s postdeadline session saw two papers on endoscopic imaging: one from a collaboration between John Hopkins Univeristy and Corning, Inc. led by Xingde Li for <a href="http://www.opticsinfobase.org/abstract.cfm?URI=CLEO:%20A%20and%20T-2012-ATh5A.1">efficient, high-resolution nonlinear endomicroscopy</a> and the other from Chris Xu’s lab of Cornell University which<a href="http://www.opticsinfobase.org/abstract.cfm?URI=CLEO:%20A%20and%20T-2012-ATh5A.2"> piggy-backed wide-field one-photon imaging with high-resloution two-photon imaging in the same device</a> for optical zoom capability. There were also a number of contributed submissions regarding advances in endoscopy such as the work by Adela Ben-Yakar’s group of the University of Texas at Austin whose endoscope used the same ultrafast laser for <a href="http://www.cleoconference.org/home/news-and-press/cleo-press-releases/medical-lightsabers-laser-scalpels-get-ultrafast,/">two-photon imaging for targeting tissue and subsurface precision microsurgery through athermal ablation</a>. Last year’s CLEO also hosted an <a href="http://www.opticsinfobase.org/abstract.cfm?URI=CLEO:%20A%20and%20T-2012-JTh3J.1">invited talk by Brett Bouma</a>, pioneer of Optical Coherence Tomography (OCT), on translating OCT into GI endoscopy.<br />
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This year’s invited speakers in <a href="http://www.cleoconference.org/home/program/invited-speakers/#AppTech">CLEOs Applications and Technology: Biomedical</a> will also be addressing future directions on endoscopes and endoscopic procedures. Invited speaker Jerome Mertz of Boston University will be discussing his work on phase contrast endomicroscopy which was <a href="http://www.nature.com/nmeth/journal/v9/n12/full/nmeth.2219.html">just published in this week’s <i>Nature Methods</i></a>. His technique cleverly uses two diametrically opposed off-axis sources to allow oblique back-illumination in a reflection mode geometry. Traditionally phase contrast microscopy using oblique illumination requires transillumination and is therefore not suitable for <i>in vivo</i> imaging. Mertz's back-illumination technique allows his microscope to be miniaturized and integrated into an endoscope for which the source and detection optics must reside on the same side of the sample. Unlike traditional oblique illumination phase contrast, Mertz's technique can be used to image thick samples.<br />
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Invited speaker Laura Marcu of University of California Davis will be addressing the use of fluorescence lifetime imaging (FLIM) and time-resolved fluorescence spectroscopy (TRFS) in clinical diagnostics. FLIM and TRFS can reveal optical molecular contrast for diagnosis of atherosclerotic cardiovascular disease. However, current approaches using FLIM and TRFS in arterial studies have been primarily <i>ex vivo</i> and <i>in vivo</i> studies have only interrogated exposed plaque. In a recent article in <i><a href="http://www.opticsinfobase.org/boe/abstract.cfm?uri=boe-3-7-1521">Journal of Biomedical Optics Express</a></i>, Marcu shows a catheter-based (“endoscopic”) scanning-TRFS system for intravascular interrogation of the arterial wall. Catheter systems are a crucial step for translating TRFS and FLIM into clinical diagnosis.<br />
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Finally, invited speaker Andrew M. Rollins of Case Western Reserve University will discuss OCT image guidance for radio frequency ablation (RFA) for treatment of ventricular tachycardia. RFA is a standard treatment for curing many cardiac arrhythmias. However, in cases of ventricular tachycardia (VT), the arrhythmia circuits are located deep in the myocardium or epicardium. Because no technology exists to image cardiac tissue directly during RFA treatment, it has limited success for curing VT. OCT which has the capability of imaging 1-2 mm deep within tissue with micron resolution could be the silver bullet for successful VT RFA procedures. In a<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912935/"> recent article in the <i>Journal of Biomedical Optics</i></a>, Rollins and collaborators from the North Ohio Heart Center, Cardiac Electrophysiology, image freshly excised swine hearts using a microscope integrated bench-top scanner and a forward imaging catheter probe to show the high functionality of OCT for RFA image guidance.<br />
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This CLEO I will be looking at imaging research from a different perspective. Whether at the research level or market-ready, advances in endoscopes serve a larger altruistic purpose of potentially giving patients a higher quality life, some control of their health, and dignity. These aren't just empty words to promote optics research but are very real. What a wonderful profession we’re in.<br />
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Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-75779605470004423882012-09-06T10:03:00.000-07:002012-09-06T14:20:32.662-07:00Ultrafast Optical Pulses and Hip Hop Play a Critical Role on Mars Rover<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUJMuF1gbHuKyKwwNDF5RIU7erPhbzZqdR2uIqAklLUQ4u2T4tsqp0K-8W9tfPIKqGZACg0mVZKzLV3lnbdJ5WXV_Q5zPIBHSPtLdGP7yl59kzbt1mCxufTGHaNRoAHHTxESx5XZb9XGY/s1600/n_NewMSL-Scene1b.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="282" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUJMuF1gbHuKyKwwNDF5RIU7erPhbzZqdR2uIqAklLUQ4u2T4tsqp0K-8W9tfPIKqGZACg0mVZKzLV3lnbdJ5WXV_Q5zPIBHSPtLdGP7yl59kzbt1mCxufTGHaNRoAHHTxESx5XZb9XGY/s400/n_NewMSL-Scene1b.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Artist Rendering of ChemCam Laser<br />
Analysis on Mars Science Laboratory. From libs.lanl.gov/ChemCam.html</td></tr>
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What do front man for the <i>Black Eyed Peas</i>, Will.i.am, and ultrafast optical pulses have in common? They are both playing crucial role on the newest Mars rover mission. On August 28, Will.i.am's song <a href="http://www.telegraph.co.uk/culture/culturevideo/musicvideo/9503245/Will.i.am-song-Reach-for-the-Stars-to-be-played-on-Mars.html">"Reach for the Stars"</a> was the first musical composition to be transmitted to Earth from another planet, in this case from <i><a href="http://www.nasa.gov/mission_pages/msl/index.html">Curiosity</a></i>, twelve days after its <i><a href="http://www.jpl.nasa.gov/video/index.cfm?id=1090">Seven Minutes of Terror</a></i> landing, complete with state-of-the-art supersonic parachute and sky-crane. I'm still a bit shocked at this science fictionesque feat of impressive engineering seeming to border on hubris. Really, a sky-crane? Really?<br />
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While Will.i.am's interplanetary music transmission is playing a critical role in science and engineering outreach as part of google+ and Lockheed Martin sponsored initiative <a href="http://www.neontommy.com/news/2011/11/william-pushes-science-education-during-rover-launch">SYSTEM</a> (Stimulating Youth for Science Technology Engineering and Math), ultrafast optics is playing a critical role for analyzing the geology of the martian surface. On August 19, <a href="http://www.msl-chemcam.com/index.php">ChemCam</a>, an instrument that is a part of the Mars Science Laboratory on board Curiosity, ablated part of a rock with ultrafast optical laser pulses and performed chemical analysis on the emitted plasma to determine rock and soil composition, a first for exogeology. Though the technique, <a href="http://libs.lanl.gov/">laser induced break-down spectroscopy</a> (LIBS), is almost as old as the laser itself, it has never been performed on another planet. What makes LIBS so useful for Mars exploration is that as an active remote sensing technique, no physical contact needs to be made with the rock or soil under test, including cleaning the sample area.<br />
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The previous Mars rovers required a rock abrasion tool to remove dust and outer layers to analyze the more interesting unweathered interior of rock and soil samples. On Curiosity, initial pulses "clean" the area and subsequent pulses create the plasma of interest whose spectrum is to be analyzed. For this instrument standoff distances can be as far as 7 m. The LIBS instrument has been combined with a Remote Micro-Imager (RMI) to give contextual information around the approximate 0.5 mm LIBS interrogation points in a single instrument called ChemCam. The figure below shows the precision of the laser system as well as the resolution of the Micro-Imager at 3 m stand-off. The choice to burn precision holes in the U.S. dollar and Euro (near Toulouse, France on the Euro map) is in homage to locations of the collaborating institutions Los Alamos National Laboratory, Centre National d'Etudes Spatiales, and Centre National de la Recherche.<br />
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<tr><td class="tr-caption" style="text-align: center;">Demonstration of ChemCam's shooting accuracy and micro imager resoltion at 3 m<br />
standoff after ablating holes in U.S. and European currency respectively. The inset<br />
(lower left) shows the difference image. Image from poster "Progress on Calibration<br />
of the ChemCam LIBS Instrument on the Mars Science Laboratory Rover," <br />
by principle investigator R.C. Weins, 2010. </td></tr>
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Besides the ultrafast laser system, ChemCam is a goldmine of optical engineering and instrumentation. There is honestly something for almost any kind of optical scientist on this instrument. Details can be found both on the ChemCam website and in a <a href="http://www.springerlink.com/content/12247284166x1871/">review of the instrument suite</a> (an easy geeky read which I had trouble putting down). The laser and imaging optics reside in the mast of ChemCam (the seeming periscope-like eye of the rover) and the spectrometers and supporting equipment live in the body unit. The mast and body are connected by optical fiber.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqWJlc6IAHh01bh6E6MQFiUIpqp5rYUozJH-gK8hiyYoOtwkJmM0Q9y_Aec2bM1XJu2JrHFnWVaPMTgqLahdVPpJ7ttz73j92gKPNoVXlL8lJCMWrEhwqQrPwnRQk5hcwJfp0-kORAQeA/s1600/image016.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="331" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqWJlc6IAHh01bh6E6MQFiUIpqp5rYUozJH-gK8hiyYoOtwkJmM0Q9y_Aec2bM1XJu2JrHFnWVaPMTgqLahdVPpJ7ttz73j92gKPNoVXlL8lJCMWrEhwqQrPwnRQk5hcwJfp0-kORAQeA/s400/image016.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Schematic of ChemCam. From "The ChemCam Instrument Suite on the Mars<br />
Science Laboratory Rover: Body Unit and Combined System Tests," Space<br />
Sci. Rev., DOI 10.1007/s11214-012-9902-4, (2012).</td></tr>
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As a laser scientist, when I read the initial news of ChemCam, I wanted to know as much as possible about the ultrafast laser on board. What kind of pulses do you need to in order to create a plasma from rock? What power? What width? What wavelength or wavelength range is required for LIBS analysis? Was it a fiber laser or solid state version?<br />
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The laser on ChemCam is a neodymium potassium gadolynium tungstate (Nd:KGW) at a center wavelength of 1067 nm made by Thayles Optronique. Pulses are 5 ns in duration with more than 10 mJ of energy in order to deliver 10 MW of power per square millimeter to the target. The repetition rate is very low, 1-10 Hz, in order to maximize pulse energy. It turns out that the wavelength is not very special and could be anything from visible to near IR- the field strength is what is most important for creating the plasma. The ChemCam team chose a laser in the 1.0 micron region due to the simplicity and practicality of obtaining the necessary energy density for LIBS. However, another advantage to choosing excitation light at 1.0 microns is that it is longer than the reddest wavelength of expected characteristic emission lines from the plasma. These lines range from 240-850 nm.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjS1_OfqyNHOsK0VpoLUTKvdSfdQjnTYYtNaW_pu37fAHEsCdTPKtH8s_YrDQmaTzTg4RIKaZAcZ5Zgb0Wv1ucnwBYfD_E-iFQa7XKdUGSea7jf0EEJTTW2dFFuLfB-rokQTlPKalX2xAU/s1600/firstspectrum.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="153" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjS1_OfqyNHOsK0VpoLUTKvdSfdQjnTYYtNaW_pu37fAHEsCdTPKtH8s_YrDQmaTzTg4RIKaZAcZ5Zgb0Wv1ucnwBYfD_E-iFQa7XKdUGSea7jf0EEJTTW2dFFuLfB-rokQTlPKalX2xAU/s640/firstspectrum.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">ChemCams first spectrum using data collected from a rock near the landing site dubbed,<br />
"Coronation". Image from Andy Shaner's ChemCam blog.</td></tr>
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So far preliminary data from ChemCam's LIBS instrument, show clean "textbook" spectra. The first spectrum (shown above) is consistent with basalt, a type of volcanic rock which is known to be present on Mars. The carbon peak in the spectrum comes from the carbon dioxide-rich martian atmosphere. Hydrogen disappeared after the first shot, indicating it was only on the surface, and the concentration of magnesium became less with subsequent lasr shots. ChemCam began ablating rocks on the martian surface August 19, and has since been taking more target practice. The latest picture from ChemCam on Augusts 25, (see below) shows a 5 x 1 raster scan to investigate chemical variability across the sample.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia7fgVEeoQoExRSDKFQxqVRrlZXOTGF0eRje4ETF6mREpVC9dJN1nRMmYE1Nb2dfyCtX2hqm7MztdK6QnSK63tfy0PpLhFEf51PUnHAkJ7pkNXKO_jXVf_2HPW89L3f2P4jTHqWcQdBn8/s1600/beechey.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="190" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia7fgVEeoQoExRSDKFQxqVRrlZXOTGF0eRje4ETF6mREpVC9dJN1nRMmYE1Nb2dfyCtX2hqm7MztdK6QnSK63tfy0PpLhFEf51PUnHAkJ7pkNXKO_jXVf_2HPW89L3f2P4jTHqWcQdBn8/s400/beechey.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A before and after photo of a 5x1 raster scan during an August 25, chemical variability analysis.</td></tr>
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The feats being accomplished by Curiosity are truly amazing. It seems the sky is the limit when it comes to what this rover can do...no wait, to quote "Reach for the Stars",<br />
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"Why do they say the sky is the limit when I've seen footprints on the moon?...let's reach for the stars"<br />
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I take that back, the stars are the limit. Thanks Will.i.am.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-70651042522748759242012-05-14T07:17:00.001-07:002012-07-22T20:39:14.857-07:00Transistor MomentFlying back home from San Jose I couldn't help wonder with excitement if our field is on the verge of a "transistor moment." Maybe it was just my CLEO conference euphoria coupled with high-end caffeine from <a href="http://www.caffefrascati.com/">Cafe Frascati</a> still in my system. However, I feel like something big is going to happen, particularly in the field of photonic circuits and nanophotonics.<br />
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The explosion of work in this subarea is impressive and CLEO hosted a number of talks from the leaders and pioneers in this field. You can still watch a handful of these on the CLEO <a href="http://www.webcastregister.com/cleo/technical.php">On Demand video</a> such as Yurii Valsov's plenary talk on fundamentals and applications of silicon nanophotonics, Larry Coldren's tutorial, CWK1.1, on single-chip transmitters and receivers, and Dave Welch's tutorial, JM4.I.1 on semiconductor photonic integrated circuits, just to name a few. Cutting edge science is interfacing with better fabrication processes- repeatability and low cost. At the poster session on Wednesday night it seemed every group was using some kind of micro ring resonator. Simple photonic circuits are becoming standard. Will our children have the nanophotonic equivalent of a Heathkit radio- something like "My first Fab." It seems a sure thing to me that my daughters will be using optical/electrical hybrid computers in their lifetime. And it seems even more certain to me that nanophotonics is the future of our field.<br />
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However, will something even bigger, more profound, and unexpected happen like when Walter Brattain dumped his amplifier experiment in a thermos of water in 1947 to successfully demonstrate electrical gain of what was to become the transistor? The same little amplifier that gave birth to a small startup company named Sony and then later to Texas Instrument, Intel and the entire business of integrated circuits and computation as we know it. The transistor was at first a "mere" amplifier. Later it became the foundation for all computer logic and a new era of technology. I wonder what is within our grasp that we don't realize.<br />
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Yurii Vlasov used imagery from the <em>Wizard of Oz</em> in his plenary talk of a road to follow to the Emerald City (our goals of nanophotonics and computation and the windy road we will take). However, I wonder what ruby slippers we are wearing right now. What "transistor potential" is waiting to be unlocked. It's a good time to be in the field of photonics. We will be the leaders of the new information age and the technology that drives and supports it.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-12283649403997211782012-05-10T16:57:00.001-07:002012-05-10T17:00:48.445-07:00Limber-up for the Postdeadline Session Tonight<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7Hvl3gnnEt3k9SiL9aoOJcQ3vipEx9XfZEY1sB5co1Xi3MFk3y5Lzze3LTBjNS7C-F3DvmPTgW4QL8wz3j3UBL_HZ3aOTIZPHdIJRHCSv6OlJnzanhsOGVt6-TS1Pji9nEPx50azM4vE/s1600/LambdaMod.png" imageanchor="1" style="font-size: 11px; line-height: 17px; margin-left: auto; margin-right: auto;"><span style="font-family: Georgia, 'Times New Roman', 'Bitstream Charter', Times, serif;"><img border="0" height="287" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7Hvl3gnnEt3k9SiL9aoOJcQ3vipEx9XfZEY1sB5co1Xi3MFk3y5Lzze3LTBjNS7C-F3DvmPTgW4QL8wz3j3UBL_HZ3aOTIZPHdIJRHCSv6OlJnzanhsOGVt6-TS1Pji9nEPx50azM4vE/s320/LambdaMod.png" width="320" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Georgia, 'Times New Roman', 'Bitstream Charter', Times, serif;"><span style="font-size: 11px; line-height: 17px;">From Postdeadline paper CTh5D.1 "Wavelength-Size Silicon Modulator." Scanning electron micrograph of the silicon integrated waveguide modulator.</span></span></td></tr>
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Make sure to stretch your legs if you want to move from session to session in this frenzy of fantastic photonics research (say that five times fast). Tonight from 8:00-10:00 pm marks the crème de la crème of contributed papers to CLEO. I haven't quite made up my mind of which to attend, but found a number of them particularly exciting:<br />
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<strong>CTh5D.1</strong>,<strong> "Wavelength-size Silicon Modulator"</strong> from V.J. Sorger et al.<br />
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This is work out of the <a href="http://xlab.me.berkeley.edu/index.html">Zhang Lab</a> from Berkely showing an optical modulator with 1-dB/micron extinction (a 20 micron long device gives 20 dB extinction). The modulator is based upon tuning the carrier concentration of an active nm-thin layer of Indium Tin Oxide sandwiched between a MOS structure. Just yesterday, Larry Coldren from UCSB was gently ribbing the silicon folk in his tutorial <strong>CW1k.1</strong>, <strong>"Single-chip Integrated Transmitters and Receivers</strong>" for the dearth of practical active components such as a modulator. Coldren sees InP based photonic circuits as the more robust platform for photonic integrated circuits. However, great work like this from the Zhang group will be pushing silicon to the forefront.<br />
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<strong>CTh5C.4, "In Vivo Three-Photon Microscopy of Subcoritical Structures wihtin an Intact Mouse Brain"</strong> from N. Horton et al.<br />
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This work from the <a href="http://research.engineering.cornell.edu/xu/">Xu Group</a> from Cornell University uses a clever choice of longer-excitation wavelength coupled to the improved localization of three photon fluorescence in order to image deep through intact tissue. Even though longer wavelengths are more readily absorbed in tissue, they are significantly less scattered. The overall effect is higher throughput and deeper penetration. Combine that with a 1/z<sup>4</sup> fall-off in three-photon fluorescence signal (tighter localization), and now you can make beautiful images of intact tissue. The Xu group shows 1.2 mm stack of brain tissue taken in 4 micron increments. The broader goal will be to eventually use this for optical biopsy in humans. I would prefer to have my tissue scanned with a laser rather than excised from my body with a knife by a surgeon, wouldn't you?
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<strong>CTh5C.1, "Demonstration of a Bright 50 Hz Repetition Rate Table-Top Soft X-Ray Laser Driven by a Diode-Pumped Laser"</strong> from B. Reagan et al.<br />
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This work from the Rocca Group of Colorado State University and the <a href="http://euverc.colostate.edu/">Research Center for Extreme Ultraviolet Science and Technology</a> shows a significant improvement of table-top soft x-ray lasers. To see how quickly this group is improving these systems, just look at a<a href="http://www.laserfocusworld.com/articles/print/volume-48/issue-03/world-news/8-8-nm-tabletop-x-ray-laser-operates-at-1-hz.html"> March 2012 Laser Focus World</a> feature article highlighting their work- now outdated. The aim of table-top soft x-ray research is to bring systems that are typically found at a shared national lab facility to the many optics tables of university labs and industry. Applications for coherent soft x-rays include laser-induced materials processing at the nanoscale level as well as ultrafast characterization of nanoscale motion. Spectra Physics or Coherent may not be selling ultrfast soft x-ray lasers just yet, but this paper shows a 5-fold increase in repetition rate (important for higher average power applications) and a 20-fold increase in pulse energy from previous best efforts.<br />
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<strong>ATh5A.4 "Highly Efficient GaAs Solar Cells with Dual Layer of Quantum Dots and a Flexible PDMS Film"</strong> from C. Lin et al.<br />
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In this paper a Taiwanese collobaration from the <a href="http://www.cop.nctu.edu.tw/classinfoview.php?lang=en&originationid=1">Institute of Photonic Systems</a>, National Chiao Tung University, and the Research Center for Applied Sciences has shown a 22 % enhanced efficiency in a GaAs solar cell by spraying a coating of UV absorptive quantum dots onto a polydimethylsiloxane film at the top surface of the cell. This collaboration has found a clever way to not let so many UV photons from the sun go to waste.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-17354233663618300152012-05-10T12:14:00.000-07:002012-05-10T12:39:31.570-07:00Protecting Troops and Civilians with Light<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="http://blog.cleoconference.org/wp-content/uploads/2012/05/IEDTraining2.jpg" style="margin-left: auto; margin-right: auto;"><img alt="" class="size-full wp-image-1331 " height="241" src="http://blog.cleoconference.org/wp-content/uploads/2012/05/IEDTraining2.jpg" width="365" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small; text-align: -webkit-auto;">From Joint IED Defeat Organization (JIEDDO) https://www.jieddo.dod.mil. Soldiers from the 713th Engineer Company, out of Valparaiso, Ind., conducted counter improvised explosive device training at Camp Atterbury Joint Maneuver Training Center Aug. 20. Photo by Staff Sgt. Matthew Scotten.</span>
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The panelists from Tuesday's 2:00 pm Market Focus,<a href="http://www.cleoconference.org/home/exhibit-displays-and-activities/market-focus/defense-laser-interrogation-for-standoff-detection/"> Defense: Laser Interrogation for Standoff Detection of Hazardous Materials</a>, presented the audience with a difficult problem to which the<a href="http://www.defense.gov/"> U.S. Department of Defense</a> is allocating many resources and substantial funding:<br />
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How can you accurately detect threats from chemical, biological, radiological, nuclear, or high-yield explosives (CBRNE) from a safe stand-off distance to protect or warn those in harms way?<br />
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Laser spectroscopy is the short answer, be it UV Raman, NIR Raman, Long Wave Absorption Spectroscopy, Laser-induced Breakdown Spectroscopy (LIBS), Photoacoustice Spectroscopy, Ultrafast Spectroscopy, just to name a few. However, what kind of spectroscopy you use to identify a threat is just the beginning to making a system that can function in rugged battlefield environments and accurately deliver the information you need in the time you need it.<br />
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Panelist Scott Robertson, Research Senior Manager at Lockheed Martin, posed just how difficult this can be with some specific targets of the type of systems needed in the field. One project whose objective was to analyze threats by the vapors and residues from vehicles needed a stand-off detection distance of 400 m, an entire scan, detect and process time of 1.0 second, with a false alarm rate of only 1 in one million, and packaged in a volume of 1 cubic meter. Another specification target was to be able to scan an area of 2,700 square meters per second while searching a road 100 m wide, while traveling 60 mph.<br />
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There are other constraints as well. Tom Stark (no relation to Tony from the Iron Man series), from Landmark Technologies Joint IED Defeat Organization, reminded the audience that 99.9% of the people in an area you want to scan are <strong>not</strong> the threat. You can't and don't want to blatently scan a crowd with a potentially dangerous high-power laser system. Another constraint therefore is laser safety, particularly eye safety. Add this to the checklist of specification targets and you start bumping up against fundamental limits for power needed to detect a spectroscopic signature of a threat, as well as selectivity and sensitivity for identification of molecules.<br />
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Augustus Fountain, Senior Research Scientist in Chemistry at Edgewood Chemical Biological Center, spoke to some of these issues. Fountain spoke about choosing the wavelength/spectroscopic for your method. In the UV you gain in sensitivity but loose in selectivity. The opposite is true as you move into the IR. Another problem to consider in system design is 1/r<sup>2</sup> loss and atmospheric attenuation. What kind of time window do you have available for scanning? Is the analyte a mixture of compounds- harder to detect spectroscopically, or something simple? Scott Roberston echoed many of these remarks. Do you want to identify the threat or do you just want to know if it is going to kill you? The specific use and system dictate different constraints on what you design. Robertson also argued most users want the latter- "just give me a green or red indicator light," not a beautiful Raman spectrum that requires interpretation. More often you just want to know "threat or no threat" for fast decision making in an environment of potential threats.<br />
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Much of the panel discussion centered around the do's and don'ts of collaborating with companies for defense money and contracts or even directly submitting proposals to broad agency announcements from DoD. If you are a small business or researcher trying to connect with defense contractors or apply directly for money the advice was to follow the rules, connect with partners and collaborators early, ask lots of questions early, and once again <strong>follow the rules</strong>.<br />
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The panel did offer some specific areas where there is need for technology. Fountain spoke how the 785 nm laser has been inappropriately the workhorse for Raman. This wavelength region has many problems. He would like sources further into the IR or deeper into the UV, particularly solid state sources. Edwin Dottery, President of Alakai Defense Systems, pleaded for a UV laser source less than 250 nm. Specifically between 220-240 nm will be ideal for UV Raman.<br />
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The difficult obstacles to overcome for practical stand-off detection are worth the effort. The end-user is particularly important and worth the time, soldiers continually putting their lives in harms way as well as civilians who want to carry on a normal life and provide for their families without fear of attacks. Lasers just may make this possible.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-16014659588437397632012-05-08T23:55:00.002-07:002012-05-09T00:22:47.007-07:00Interest in 2.0 micron Light is Growing<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_W6Z92hrKj8BdkPV2sGmQ-9hiXzUPFwFfvsuXEPYRgxwXar7JOlzUe0FYdhrEsglnPBwIcw-PNXE8zNcA-gUtKIBuPrq_OKlMkTdp5ZCW-iNyd8F2pmlKn_kg8ATjnp3__KQnKm_N2_Y/s1600/Trace.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_W6Z92hrKj8BdkPV2sGmQ-9hiXzUPFwFfvsuXEPYRgxwXar7JOlzUe0FYdhrEsglnPBwIcw-PNXE8zNcA-gUtKIBuPrq_OKlMkTdp5ZCW-iNyd8F2pmlKn_kg8ATjnp3__KQnKm_N2_Y/s400/Trace.png" width="400" /></a></td></tr>
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Wavelength Modulation Spectrum using tunable 2.0 micron VCSEL; From <b>JTh1L.6</b>, A. Kahn et al,. "Open-Path Green House Gas Sensor for UAV Applications"</div>
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Today at CLEO I spent a large amount of time at the expo hunting down which companies were selling 2.0 micron wavelength products and why. In the technical program, there are a large number of contributed talks regarding 2.0 micron lasers, pulsed and continuous wave. On Monday I attended session <b>CM1B, Ultrafast Mid-IR</b> in which 5 out of 8 papers demonstrated ultrafast pulses about 2.0 microns. Today there was a session titled<b> CTu2D,</b> <b>1.5 to 5 micron Lasers</b> which also had 5 talks out of 8 showing laser systems operating near 2.0 microns. There have been and will be a handful of talks not pinned down to these topic categories as well:<br />
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<b>-CM2B.2,</b> "A Broadband 1850-nm 40-Gb/s Receiver Based on Four-Wave Mixing in Silicon Waveguides"<br />
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<b>-CTu3M.7,</b> "All-fiber 10-GHz Picosecond Pulse Generation at 1.9 microns without Mode-locking"<br />
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<b>-JTh1L.6</b>, "Open-Path Green House Gas Sensor for UAV Applications"<br />
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<b>-CF1K.1,</b> "Single-Frequency kHz-Linewidth 2-μm GaSb-Based Semiconductor Disk Lasers With Multiple-Watt Output Power"
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<b>-CF1N.4</b>, "Double-wall carbon nanotube
Q-switched and Mode-locked Two-micron Fiber Lasers" </div>
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However, what we like to research and what we can actually bring to market are often two very different things. I am therefore excited that it is not just 2.0 micron papers that are cropping up at this years conference, but 2.0 micron products at the expo as well.</div>
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So why is anyone interested in light in the 2.0 micron region? My personal interest stems from a research talk I saw by analytical chemist, <a href="http://ostc.physics.uiowa.edu/~arg/">Mark Arnold</a>, at University of Iowa. Arnold is trying to perform some hard analytical chemistry on 2.0 micron light shone through the skin on the back of one's hand. He hopes that by looking at the absorption spectra, he can measure blood glucose levels without having to draw blood. This noninvasive testing would be a boon to diabetics who are not thrilled about pricking their fingers regularly. Wavelengths that are helpful for pinning down glucose, but that are not absorbed as readily by tissue are 2.13 microns, 2.27 microns, and 2.33 microns.</div>
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In short, there are some interesting molecules around 2.0 microns on which to perform spectroscopy. For environmental sensing, there is 1877 nm, a well defined water absorption line, and 2004 nm, a good line for carbon dioxide detection, and many more.</div>
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Many of the companies I spoke with selling 2.0 micron components and sources confirmed such spectroscopic applications of their customers:</div>
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-<a href="http://ozoptics.com/">Oz Optics</a> now sells passive fiber components at 2.0 microns as well as DFB sources.</div>
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-<a href="http://www.sacher-laser.com/">Sacher Lasertchnik</a> and <a href="http://www.nanoplus.com/">Nanoplus</a> make DFB lasers extending through the 2.0 micron region depending on your molecule of interest.</div>
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-<a href="http://www.advaluephotonics.com/">Advalue Photonics</a> makes thulium-based fiber laser systems and sells passive 2.0 micron products.</div>
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-<a href="http://search.newport.com/?i/1/q1/Products/q2/New+Focus+Products/x1/pageType/x2/product_brand/nav/1/view/brand/">New Focus</a> will be developing tunable laser diodes about 2.0 microns in the next few months.</div>
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-<a href="http://www.nufern.com/">Nufern</a> and <a href="http://www.coractive.com/">CorActive</a> are selling Tm- and Ho-doped fiber for 2.0 micron amplification and for fiber sources.</div>
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-<a href="http://www.ipgphotonics.com/">IPG</a> sells a number of lasers from 2.0-2.8 microns based Cr:ZnSe as well as 2.0 micron fiber lasers using thulium doped fibers.</div>
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There are other advantages to 2.0 micron light as well. 2.2 microns is where the two-photon absorption coefficient in silicon drops to nothing. If you are interested in confining light to a silicon waveguide, doing so at 1550 nm could be the worst choice since it coincides with the peak two-photon absorption. However, above 2.2 microns allows higher throughput as well as access to other nonlinear effects like parametric amplification. </div>
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This is one of the pursuits of Thorlab startup, <a href="http://www.picoluz.com/">PicoLuz</a>. Among other optical instrumentation, <a href="http://www.picoluz.com/">PicoLuz</a> is developing 2.0 micron amplifiers which will eventually support its endeavors of a chip scale optical parametric amplification. </div>
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-<a href="http://www.thorlabs.com/">Thorlab's</a> Quantum electronics division is also selling a laser that is tunable about the gain bandwidth of thulium 1800-2000 nm, an FTIR spectrometer that goes out to 2500 nm, a handful of moderate speed long-wavelength detectors, passive fiber components for 2.0 microns, as well as pumps for Tm-amplifiers.</div>
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Another reason for generating 2.0 micron light is for opening up new spectral bandwidth for telecommunications or signal processing, whether on fiber or on silicon. To that end,</div>
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-<a href="http://www.eospace.com/">Eospace</a> is now offering 20 Gb/s speed LiNbO3 intensity and phase modulators at 2.0 microns.</div>
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-<a href="http://www.eotech.com/">Electro-Optics Technology</a> is pushing past 1 GHz speed for 2.0 micron detectors.</div>
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Malcom Minty, a project manager from New Focus told me that New Focus was actively persuing thulium based laser systems in the 90's. The thought was that bandwidth would all be used up in the C- and L-band during the telecom boom, requiring expansion. Thulium has wide efficient gain and was a natural choice. Nufocus dumped the project as the the telecom bubble burst. Now they will be rejuvenating it, but more likely to sell to customers interested in spectrscopic pursuits.</div>
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Minty conjectured that 2.0 microns is becoming an interesting color to customers, vendors and researchers because it is in a region (or getting close to a region) of spectrscopic and biomedical interest. However, because it is close enough to the L-band, much telecom technology can still be used. It just squeaks by with some efficiency for detection on InGaAs-based detectors where as detection methods above 3.0 microns start getting tricky.</div>
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I think Minty likely has this right. If so I will be interested to see what new research we can carryout with 2.0 micron light while leveraging what we already know from fiber systems and telecom.</div>Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-16413268474623829982012-03-25T21:16:00.039-07:002012-03-29T21:30:15.744-07:00Highlights from the Program Chairs<object style="height: 260px; width: 427px"><param name="movie" value="http://www.youtube.com/v/GC-L6kgha0k?version=3&feature=player_detailpage"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/GC-L6kgha0k?version=3&feature=player_detailpage" type="application/x-shockwave-flash" allowfullscreen="true" allowscriptaccess="always" height="260" width="427"></embed></object><br /><span style="font-style: italic;font-size:85%;" >(One of seventeen youtube shorts from the program chairs highlighting hot topics for CLEO 2012)</span><br /><br />For a few years now CLEO conference organizers have been posting youtube shorts highlighting contributed talks, symposia, research trends, and any new or unique directions for the upcoming conference. This year there are seventeen videos from the program chairs, all worth watching. However, for those who prefer text over A/V, I thought it might be helpful to highlight the highlights here.<br /><br /><span style="font-weight: bold;">Conference Program Stats</span><br /><br />-The 2012 program has been selected from a record number of submissions.<br /><br />-In just its second year, CLEO's new Technology and Applications Conference saw a 50 % increase in submissions.<br /><br />-350 papers, 15 % of all submissions, live in the subcommittee sections "Nano-optics and Plasmonics" or "Micro- and Nano-Photonic Devices"<br /><br />-Subcommittee section: "Fiber Amplifiers, Lasers and Devices" was the single committee that received the most submissions<br /><br /><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Defense.aspx"><span style="font-weight: bold;">CLEO Applications and Technology</span>: <span style="font-weight: bold;">Government and National Science, Security and Standards Applications</span></a><br /><br />In his youtube short, subcommittee Chair Ian Mckinnie of Lockheed Martin Coherent Technologies briefly discusses the two tracks of this subcommittee: 1) Ultrafast Laser Applications and 2) Instrumentation and Sensing.<br /><br />Mckinnie talks about how the ultrafast program covers a broad range ultrafast laser applications spanning those performed at large facility-class systems to those on a bench top or operating table. These are exemplified by the tutorial talk, AW3J1, "Enabling Science at the Advanced Light Source X-ray Facility" that will be given by Roger Falcone of Lawrence Berkeley National Laboratory from 4:30-5:30 pm on May 9, and the invited talk AW3J4, "Applications of Ultrafast Lasers" by Mike Mielke of Raydiance Inc., also on May 9, but from 6:00-6:30 pm<br /><br />The <a href="http://www-als.lbl.gov/">Advanced Light Source</a> (ALS) is a large synchrotron source that produces laser light over an extremely broad spectrum including the hard-to-reach soft x-ray region. Falcone will be discussing the use of the coherent radiation at this user-facility for applications such as precise material processing and biomedical research.<br /><br />On the other hand, Mielke will be discussing the use of compact fiber systems for micromachining and laser surgery. See blog post <a href="http://cleoqels2010.blogspot.com/2011/12/machining-with-ultrafast-pulses.html">"Machining with Ultrafast Pulses"</a> for some stunning videos and more information on these compact micromachining systems.<br /><br />On the remote sensing side, Massayuki Fujita, from the Institute of for Laser Technology in Osaka, will be giving an invited talk on an application of remote sensing not typically found in the CLEO conference program- nondestructive inspection for heavy industrial processes. Fujita's talk, ATuG3 "Nondestructive Inspection for Heavy Construction" can be heard on Tuesday May 8, at 2:30 pm.<br /><br /><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Biomedical.aspx"><span style="font-weight: bold;">CLEO Applications and Technology</span>: </a><span style="font-weight: bold;"><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Biomedical.aspx">Biomedical</a><br /></span><br />In his youtube short, subcommitee chair Yu Chen from University of Maryland mentions a number of specific talks you won't want to miss:<br /><br />In the session "<span style="font-style: italic;">In vivo</span> Imaging", there will be two talks on on image-guided spectroscopy. The first will be a tutorial talk by Brian Pogue of Dartmouth on integrating optical molecular spectroscopy techniques into standard medical imaging equipment, ATh4C1, "Image-Guided Spectroscopy of Cancer: Translating Optical Technology into Clinical Tools" on May 10, at 4:30 pm. The second will be an invited talk from Brian Benaron of Spectros Corporation, ATh4C4, "Molecular Spectroscopy and Imaging: A multibillion-dollar industry reshaping biotech and medicine" also on May 10, but 6:00 pm.<br /><br />Chen also mentions the contributed talks from the In Vivo session by Saivash Yazdanfar of GE Global Research who will be speaking about fluorescence image-guided procedures in talk ATh4C2, "Fluorescence Image Guided Surgical Instruments and Contrast Agents for Intraoperative Visualization of Nerves" on May 10, 5:30 pm as well as contributed talk from Adam Straub of Cornell University who will be presenting work on increasing multi-photon image acquisition speed by a whopping two orders of magnitude, ATh4C3, "Multiphoton Multifoci Modulation Microscopy for High-Speed Fluorescence Lifetime Imaging"at 5:45 pm on May 10.<br /><br />Chen goes on to highlight other talks in session "OCT and Microscopy" which will be held on Thursday May 10, from 2:00-4:00 pm, perhaps most notably talk JTh3J, "Recent advances in translating OCT into GI Endoscopy" by Brett Bouma of Massachusetts General Hospital, one of the pioneers of OCT. There will also be a host of cutting edge talks in session "Cellular Imaging and Therapy" 8:00-10:00 am on Thursday May 10. This session kicks off with an invited talk by Adam Wax from Duke University<span class="pagecontents">, </span>ATh1M1, <span class="pagecontents">entitled "Coherence Imaging for Early Cancer Detection."<br /><br /></span><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Industrial.aspx"><span style="font-weight: bold;">CLEO Applications and Technology</span>: </a><span style="font-weight: bold;"><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Industrial.aspx">Industrial Applications</a><br /></span><br />In his video short, subcommittee chair Eric Mottay of Amplitude Systemes discuses the two major trends of the Industrial Applications subcommittee: 1) micro- and nanofabrication techniques and 2) applications of graphene.<br /><br />Talks in the latter category can be found in a joint session with CLEO: Science and Innovation subcommittee six in session "Graphene and Carbon Advanced Photonic Materials" which will be held form 11:00am-1:00 pm on May 8. This session will host talks presenting graphene-based devices such as detectors, modulators, and tunable resonators. Recall that Andre Geim and Konstantin Novoselov were awarded the <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2010/press.html">2010 Nobel Prize</a> for showing the "exceptional" properties of graphene such as it being simultaneously the thinnest and strongest material, having better electrical conductivity than copper, better heat conduction than all other known materials, and having nearly 100 % transparency yet an extremely high density (so dense helium atoms cannot pass through). Be sure to see how this "magical" material is being translated into devices that may be on the market in the next three to five years.<br /><br />On the other hand, the invited talks for this subcommitee all center around micro- and nano- fabrication processes. Arnold Gillner of the Fraunhofer Institute will discuss how ultrafast lasers can be used for surface processing at the micro- and nanoscale level for applications in light guiding, fabrication of low friction surfaces, or wear-resistant surfaces. His talk, ATu3L1, "Micromanufacturing and nano surface functionalisation with ultrashort pulsed lasers" is scheduled for May 8, at 4:30 pm. Additionally, Paul Webster from Queen's University will be discussing online monitoring during fabrication, particularly concerning the control of depth, in invited talk ATu3L5, "Inline Coherent Imaging: Measuring and Controlling Depth in Industrial Laser Processes," on May 8, at 5:45 pm and Rick Russo from Lawrence Berkeley National Laboratory will be speaking about real-time spectroscopy of a sample after it has been turned into a plasma through laser ablation in talk, AW1H3 "Laser Plasmas for Spectrochemistry" on May 9, at 11:00 am.<br /><span class="pagecontents"><br /></span><a href="http://www.cleoconference.org/Home/Applications-and-Technology/Core-Tracks/Energy.aspx"><span style="font-weight: bold;">CLEO Applications and Technology</span>: <span style="font-weight: bold;">Energy and Environment</span></a><br /><br />In his video short, subcommittee chair Christian Wetzel from Rensselaer Polytechnich Institute discusses two trends in paper submissions 1) environmental sensing, particularly atmospheric sensing using quantum cascade lasers (QCL) and 2) Breakthroughs in LED lighting, for which many contributed papers address ways of overcoming "droop" (the reduction in efficiency by when driving with high current).<br /><br />These two topics will be also be discussed indirectly and directly in the special symposium "50th Anniversary of the Semiconductor Laser" in which one of the pioneers of the QCL, Jerome Faist, from the Institute of Quantum Electronics in Zurich, will be giving an invited talk "Quantum Cascade Lasers: Coming of Age" as well in the plenary talk, "Development of nonpolar and semipolar InGaN/GaN light-emitting diodes (LEDs) and Laser Diodes" by solid-state lighting giant Steven Denbaars of University of California, Santa Barbara<em></em>.<br /><br />Wetzel mentions two must-see invited talks in his short. One is talk JTh4J1 "Hydrogen Generation using Nitride Photoelectrode" by Kazuhiro Ohkawa of Tokoyo University of Science on May 10, at 4:30 pm. Ohkawa will show results of solar powered water-splitting on a nitride-based electrode for which the incident photon-to-electron conversion efficiency (IPCE) is upwards of 70%. The other is JTh1L3, "III-Nitride Optochemical Nanosensors" in which Jörg Teubert from <span class="pagecontents">Justus-Liebig-University in Giessen</span> will discuss a nitride-based nanosensor for spectroscopic measurement and ph detection.<br /><br /><a href="http://www.cleoconference.org/Home/About-CLEO/CLEO-Committees.aspx#ScienceInnovations"><span style="font-weight: bold;">CLEO: Science and Innovation</span></a><br /><br />In his youtube short, program co-chair René-Jean Essiambre of Bell Labs, Alcatel-Lucent discusses some of the trends of the various committees.<br /><br />In subcommittee 11: Fiber Amplifiers, Lasers and Devices, Essiambre notes a trend in papers demonstrating lasers between 1.8-2.0 microns. This is a region where thulium and holmium give efficient and broad gain. Specifically, many submissions show increased wavelength tunability or higher-power operation. Since Essiambre mentions this track, I figured this would give me license to shamelessly promote my own contributed talk. I will be presenting a contributed paper in this category, CTu3M7, "All-fiber 10-GHz Picosecond-Pulse Generation at 1.9 μm without Mode-locking" which demonstrates an unconventional method for pulse generation in this spectral region.<br /><br />What is so exciting about 2.0 micron light is that there are good gain media in this spectral region and it is just on the edge of the mid-IR for which spectral signatures for various interesting molecules have sharp unique absorption lines- the fingerprint region. Therefore, 2.0 micron sources may be good seed sources to frequency-shift to redder, more spectroscopically significant wavelengths. Two micron light also holds interest for silicon photonics since two-photon absorption, a hindrance for many processes involving tightly confined and/or pulsed light, drops off rapidly in silicon at 2.0 microns and beyond.<br /><br />Essiambre also notes other trends in the various subcommittees in Science and Innovations. In subcommitee 12: Lightwave Communications and Optical Networks many submissions address new modulation formats and constellations, spatial multiplexing, and high spectral efficiency systems.<br /><br />Subcommittee 13: Active Optical Sensing saw a focus on frequency combs, particularly making comb sources more accurate, with narrower line-widths, yet at the same time keeping them simple, portable, inexpensive and usable in harsh environments. This was also the trend for papers submitted to subcommittee 14: Optical Metrology. In addition, topics for this subcommittee address applications to astronomy, spectroscopy, and use for high precision standards, not to mention distribution of high-precision combs.<br /><br />Check out the <a href="http://www.youtube.com/playlist?list=PL4B4482F7CC0C3B9F">videos</a> for more details and information. One of the marvelous things about CLEO is that it has so much breadth and hosts so many talks. However, this also makes it overwhelming and difficult to decide what to attend and to decipher new trends in research and applications. I recommend taking some time to hear what the chairs have to say so that they can make your work a little easier.<br /><span style="font-weight: bold;"></span>Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-842519977505106112012-02-27T21:07:00.020-08:002012-03-30T11:35:25.153-07:00Semiconductor Laser's Golden Anniversary<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg28o0ZQ7Ye1EEmhjGJmN3VZSHZyCHFYVBb3yz_W_s9P84DOgP2MBVqbALSAsB2qy_2k2zCEvwqil4T6SQCB2Zg1GriFLfrt5RFuzNsvE8N6EDJMK3C3zOhCcTxWNAZkwh6q3cHrSklQgc/s1600/Nanolaser.png"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 400px; height: 204px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg28o0ZQ7Ye1EEmhjGJmN3VZSHZyCHFYVBb3yz_W_s9P84DOgP2MBVqbALSAsB2qy_2k2zCEvwqil4T6SQCB2Zg1GriFLfrt5RFuzNsvE8N6EDJMK3C3zOhCcTxWNAZkwh6q3cHrSklQgc/s400/Nanolaser.png" alt="" id="BLOGGER_PHOTO_ID_5714228213955073234" border="0" /></a><span style="font-style: italic;font-size:85%;" >(Above: First room temp. CW semiconductor nanolaser with subwavelngth cavity presented at CLEO 2011. From K. Ding et al, CTuG2, CLEO 2011.)</span><br /><br />The year 2012 marks the impressive <a href="http://www.cleoconference.org/Home/Science-and-Innovations/Special-Symposia.aspx#semiconductor">50th anniversary</a> of the invention of the prolific and ubiquitous semiconductor laser. Almost every household in the industrialized world owns at least one, be it in a DVD player (maybe two if it is a Blue-ray), CD player, optical mouse or depend on them indirectly for long-distance phone service, digital cable, or internet access. Besides making telecommunications a practical possibility, semiconductor lasers have paved the way for the development of silicon photonics and will be pivotal in the future of optical information storage and processing. Despite their primary use in mass consumer markets for communications, information processing, mutimedia, and <a href="http://www.petco.com/product/7181/Miracle-Beam-Laser-Pet-Toy.aspx">teasing cats</a> (you can even get semiconductor laser pointers with phase masks and lens attachments that project images mice or fish on the floor for your feline to chase), many subfields have profited from the low-cost and small-footprint of these robust laser sources. Take for example the handful of semiconductor sources offered <a href="http://www.thorlabs.com/navigation.cfm?Guide_ID=2111">commercially by Thorlabs for optical coherence tomography</a>, or the inexpensive semiconductor laser diode sources used by the Ozcan group for <a href="http://cleoqels2010.blogspot.com/2011/09/photonics-for-global-health.html">field-portable, ultra-low footprint, holographic microscopes</a>.<br /><br />There are too many other technologies and subfields to name that have profited as well. All you need to do is think of the numerous optics applications that live at telecom wavelengths near 1300 nm or 1550 nm or DVD player wavelengths, 405 nm and 635 nm. Such lasers offer unbelievable device characteristics at such a low price that researchers and venture capitalists often build their technologies to fit these wavelengths instead of the other way around.<br /><br />Amnon Yariv and Pochi Yeh write in their 2007 edition of the book <span style="font-style: italic;">Photonics</span> that,<br /><br />"The semiconductor laser invented in 1961 is the first laser to make the transition from a research topic and specialized applications to the mass consumer market...It is by economic standards and the degree of its applications, the most important of all lasers."<br /><br />To celebrate the most important laser of lasers, CLEO will be hosting a <a href="http://www.cleoconference.org/Home/Science-and-Innovations/Special-Symposia.aspx#semiconductor">special symposium</a> with talks from pioneers of semiconductor laser technology. The list of speakers and subjects has been well-crafted to paint not only a historical picture but to address current research and trends on this ever-evolving technology.<br /><br />From a fundamentals perspective Russel Dupuis from Georgia Tech will be talking about device materials. Nobel Laureate <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2000/kroemer.html">Herbert Kroemer</a> of University of California Santa Barbara will discuss the double heterostructure which is still the basic framework for almost all semiconductor light sources and solar cells and which without there would be no continuous wave (CW) lasing in semiconductor devices at room temperature. To this end, Morton Panish, formerly of Bell Laboratories, will describe the development of the first room temperature semiconductor laser.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDQB_jrjQaqP2sSqSExRT2sqGsHG46yMtPlMwCdJjQGZ0wY2ssZNKnDgoNMDGwi5k2PbSqc_HelYBQXJ34iIPCSIK1IyiFCXIJ1bxhTNmtZZDsDKyksjbblc_ySvXsDdgsbzgju9CDSaI/s1600/Threshold.png"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 400px; height: 348px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDQB_jrjQaqP2sSqSExRT2sqGsHG46yMtPlMwCdJjQGZ0wY2ssZNKnDgoNMDGwi5k2PbSqc_HelYBQXJ34iIPCSIK1IyiFCXIJ1bxhTNmtZZDsDKyksjbblc_ySvXsDdgsbzgju9CDSaI/s400/Threshold.png" alt="" id="BLOGGER_PHOTO_ID_5714229785807423282" border="0" /></a><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><span style="font-size:85%;"><span style="font-style: italic;">(Above: Evolution of threshold current. From Nobel Laureate <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2000/alferov.html">Z. Alferov</a>, IEEE J. Sel. Top. Quant. Elec. 6, 832, 2000.)</span></span><br /><br />Charles Henry, formerly of Bell Laboratories, will discuss the quantum well structure which was pivotal in reducing active layer thickness and therefore significantly reducing threshold current, see the figure above. Yasuhiko Arakawa from the University of Tokyo will discuss quantum dot lasers which reduced threshold densities even further and remains a developing area of semiconductor laser physics research.<br /><br />On the more practical side, Jack Jewell, of Green VCSEL will discuss the vertical cavity surface emitting laser (VCSEL) which among other important device attributes may be the <a href="http://princetonoptronics.com/technology/technology.php#1">best laser for high-yield production</a>. VCSELs are grown, processed, and tested in wafer-form allowing parallel fabrication and testing, minimizing labor and maximizing yield. They also take up less space on a wafer- about three times less than edge emitters of similar power and can be made in 2-D arrays. Jewell will likely discuss the benefits of <a href="http://eetimes.com/General/PrintView/4078885">lower power consumption</a> of VCSELs for use in short-reach, high-speed networks. My understanding is that the "green" in "Green VCSEL" refers to environmental considerations not wavelength.<br /><br />There will also be talks discussing the semiconductor laser's role in telecommunications, quantum cascade lasers, integrated and hybrid optical circuits, high-power devices, as well progress in nano laser structures with subwavelength volume (see the figure at the top).<br /><br />Whether to learn the history, fundamental principles, pay homage to the pioneers, or to learn new trends, be sure to mark your calendar for the <a href="http://www.cleoconference.org/Home/Science-and-Innovations/Special-Symposia.aspx#semiconductor">50th Anniversary of the Semiconductor Laser</a> symposium to celebrate "the most important of all lasers."Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com1tag:blogger.com,1999:blog-8860229920122250605.post-14883115513416373222012-01-26T13:14:00.000-08:002012-01-26T20:10:37.196-08:00Why a Temporal-Cloak is so Great: Uncovering the Hype<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7eSBUTgskAGE-qfgF_CYbuS1g_PiyHw0W9scxVKALkeDf3W8pnaIR9npvdJYIYgFZm9mV-lRxQzERdtqey208Cqr0IQjNcmx-ErJ8eq4c0G-a3tbmroY31SoAMKBDPxxgOr8oKHXRItI/s1600/CloakingExplanation.png"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 394px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7eSBUTgskAGE-qfgF_CYbuS1g_PiyHw0W9scxVKALkeDf3W8pnaIR9npvdJYIYgFZm9mV-lRxQzERdtqey208Cqr0IQjNcmx-ErJ8eq4c0G-a3tbmroY31SoAMKBDPxxgOr8oKHXRItI/s400/CloakingExplanation.png" alt="" id="BLOGGER_PHOTO_ID_5702155232717087938" border="0" /></a><br style="font-style: italic;"><span style="font-size:85%;"><span style="font-style: italic;">(Figure from R. Boyd and Z. Shi, Jan. 5, "News and Views" Nature, explaining temporal-cloaking)</span></span><br /><br />At Frontiers in Optics 2011 just this last October, Moti Fridman from Alex Gaeta's group presented work on a the first experimental demonstration of <a href="http://www.osa.org/About_Osa/Newsroom/News_Releases/Releases/10.2011/Temporal-Cloaks-Adjust-Lights-Throttle.aspx">temporal-cloaking</a> using a <a href="http://cleoqels2010.blogspot.com/2011/05/time-lens-20.html">time-lens</a> system. The work was based upon a theoretical paper from <a href="http://iopscience.iop.org/2040-8986/13/2/024003">Martin McCall <span style="font-style: italic;">et a</span>l</a> in the February issue of the <span style="font-style: italic;">Journal of Optics, </span>and at the beginning of this month, appeared in an <a href="http://www.nature.com/nature/journal/v481/n7379/full/nature10695.html">in-depth treatment</a> in the January 5, issue of <span style="font-style: italic;">Nature</span>. Besides the usual barrage of bloggers latching onto science-fictionesque results of new research, time-cloaking was also written up in traditional news media such as the <a href="http://www.csmonitor.com/Science/2012/0104/Time-cloaking-how-scientists-opened-a-hidden-gap-in-time">Christian Science Monitor</a>.<br /><br />Temporal-cloaking certainly sounds like something out of <span style="font-style: italic;">Star Trek</span>, but what is it and why is it so great? What makes a temporal cloak truly exciting, and what a majority of the recent articles and posts fail to highlight, is that the temporal-cloak allows cloaking over an <span style="font-weight: bold;">infinite section of space</span> albeit for a finite duration of time.<br /><br />Let's imagine Harry Potter and his invisibility cloak. If the invisibility cloak is a temporal-cloak, Harry can move as far as he wants to the left-and-right and up-and-down without being seen for duration of the cloaking window. Harry can also move a little bit forward and backward without being seen, but not much or else he will walk out of the cloaking time-window (which is 50 ps for the Gaeta group's work or about 1.0 cm in fiber). It is crucial that he is in the right place in the axial dimension (forward/backward) since the window occurs at a specific place in space, but he has total freedom in the transverse dimension for the duration of the cloak. Conceivably Harry could pull-off a bank robbery as long as the bank and the vault are inside that particular infinite pancake of cloaking window and within the duration of the window.<br /><br />Contrast that to a spatial cloak which gives cloaking for an <span style="font-weight: bold;">infinite amount of time</span>, but only a finite section of space. If Harry has a spatial invisibility cloak, then he can stand in one spot for as long as he wants without being seen.<br /><br />Finally, if Harry has a spatio-temporal cloak, conceivably he can maintain invisibility for any duration of time and throughout any volume of space.<br /><br />The temporal-cloak shown by the Gaeta group is not a practical cloak. If you scrutinize the setup you'll find that the way that they detect a cloaked event is through lack of nonlinear mixing. A nonlinear signal tells them the event is detected, and no signal tells them that the event is cloaked. You could just turn the power down to get the same result. They also couple into and out of the cloaking window with fiber-couplers between the cloaking apparatus. You can't send both the signal and the event to be cloaked down the same fiber because if the "event" goes through the same time-lens system as the "signal" the event will appear superposed instead of cloaked. Basically they had to sneak it into the right spot at the right time along a different path of propagation.<br /><br />However, the point of the work was not to show practical temporal cloaking for masking or encryption, but to show the very odd, very fundamental, and very cool phenomena of creating and tailoring gaps in time. So even if the temporal-cloak won't be used anytime in the near future for cracking safes, it does bring the optics community closer to a true spatio-temporal invisibility cloak. It might be time to start brushing up on the rules of Quidditch.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-26473013158925561622011-12-12T07:30:00.000-08:002011-12-13T09:20:46.233-08:00Machining with Ultrafast Pulses<object style="height: 195px; width: 320px"><param name="movie" value="http://www.youtube.com/v/2YobSbzNGjw?version=3&feature=player_detailpage"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/2YobSbzNGjw?version=3&feature=player_detailpage" type="application/x-shockwave-flash" allowfullscreen="true" allowscriptaccess="always" height="180" width="320"></embed></object><br /><span style="font-style: italic;">(From Raydiance Inc)</span><br /><span style="display: block;" id="formatbar_Buttons"><span onmouseover="ButtonHoverOn(this);" onmouseout="ButtonHoverOff(this);" onmouseup="" onmousedown="CheckFormatting(event);FormatbarButton('richeditorframe', this, 8);ButtonMouseDown(this);" class=" down" style="display: block;" id="formatbar_CreateLink" title="Link"></span></span><br />As someone who has been trying to design novel ultrafast laser systems for the past eight years, my eyes were drawn to the title <span style="font-weight: bold;">"Applications of Ultrafast Lasers"</span> of Dr. Mike Mielke's talk from Raydiance, Inc. from the awesomely overwhelming list of<a href="http://www.cleoconference.org/Home/Program/Invited-Speakers.aspx"> invited speakers</a> at CLEO 2012. Dr. Mielke's talk is one of a handful in CLEO's new Application and Technology conference which debuted last year in Baltimore in order to better bridge the gap between fundamental research and product commercialization.<br /><br />To see what background information I could potentially find, I went to<a href="http://www.raydiance.com/"> Raydiance's website</a> to find a wealth of information on micromachining and a host of video shorts of ultrafast laser micromachining in action. They are so pleasing to watch, I couldn't help embedding many of them in this post.<br /><br />Micromachinging with ultrafast lasers allows the removal of material without the introduction of heat (see the video above of laser micromachining on a match head without it igniting). Ultrafast lasers therefore give the advantages of laser machining- tailoring submicron features on the workpiece, without thermal collateral damage. For example, if you are going to have your dentist drill a tiny hole in one of your teeth (see the figure below) , you'd rather have her use the 350 fs laser shown in b) rather than 1.4 ns laser in a) in which the heat generated damages and fractures the tooth.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgR0Oert7SjSfs4UqWP37kkclyb3uhhXeg1kvcPoAIHxD9tiyTcZ9ZqeHtZaNpUzdTiH-JVJ45_8XhlVarOmXHVOW6zYF6Q34JJCAwii5sUP0Rml1gjWUtGOcqkQcFPtVKvl6bssmaWPA/s1600/tooth.png"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 400px; height: 199px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgR0Oert7SjSfs4UqWP37kkclyb3uhhXeg1kvcPoAIHxD9tiyTcZ9ZqeHtZaNpUzdTiH-JVJ45_8XhlVarOmXHVOW6zYF6Q34JJCAwii5sUP0Rml1gjWUtGOcqkQcFPtVKvl6bssmaWPA/s400/tooth.png" alt="" id="BLOGGER_PHOTO_ID_5685290363539970018" border="0" /></a><br /><span style="font-size:85%;"><br /><span style="font-style: italic;">(Above: Drilling tooth enamel with a) 1.4 ns 30 J/cm</span><sup style="font-style: italic;">2 </sup><span style="font-style: italic;">laser pulses and b) with 350 fs 3 J/cm</span><sup style="font-style: italic;">2 </sup><span style="font-style: italic;">pulses. From B.C. <a href="http://www.osti.gov/bridge/servlets/purl/310888-caHrw7/webviewable/310888.pdf">Stuart et al LLNL</a>.)</span></span><br /><br />This is because drilling with the femtosecond pulses relies on an entirely different physical process for removal of material than nanosecond pulses. For long pulses (> 100 ps), photons are absorbed by the material and converted into heat. This eventually fractures, melts, or vaporizes material at (and nearby) the laser focus. On the other hand, if the pulse is fast enough (< 1 ps), the material is removed solely by photo-ionization. Rather than dumping energy into the material, electrons of target molecules are stripped off by the intense electric field of the pulse. No absorption takes place and therefore no heat is generated.<br /><br />Because the mechanism for material removal using ultrafast pulses does not depend on the material properties as it does for thermal ablation, such as the melting point, conceivably <span style="font-weight: bold;">any material</span> can be machined using ultrafast pulses. This has allowed Raydiance to micromachine polymeric materials for manufacturing next-generation vascular stents and microfluidic devices (see the videos below).<br /><br /><object style="height: 195px; width: 320px"><param name="movie" value="http://www.youtube.com/v/lDiYj_Pl_3U?version=3&feature=player_detailpage"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/lDiYj_Pl_3U?version=3&feature=player_detailpage" type="application/x-shockwave-flash" allowfullscreen="true" allowscriptaccess="always" height="180" width="320"></embed></object><br /><span style="font-style: italic;">(From Raydiance Inc)</span><br /><br />Though micromachining using ultrafast lasers is not new, doing so in a robust workstation-platform is. Raydiance touts to have created the first "industrial grade" femtosecond laser platform. They have an impressive record and a current partnership with ROFIN GmbH for the development of industrial-grade femtosecond laser micromachining workstations. In the literature on their website they state, "A laser is not a solution. It might be the engine of a solution, however, 21st century manufacturing floors demand more: software integration, beam delivery, motion control, and visioning systems." As an "engine builder" myself it is helpful to know just what kind of engine is the most useful to workstation integration. Sometimes "engine builders" get caught up in making Formula One cars when what is most helpful is a reliable Hyundai sedan. Although not any pulse width, energy, and rep will do for athermal ablation, neither will a workstation without robust, continuous (thousands of hours 24/7), turn-key operation.<br /><br /><object style="height: 195px; width: 320px"><param name="movie" value="http://www.youtube.com/v/Ymp6iKLrpsE?version=3&feature=player_detailpage"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/Ymp6iKLrpsE?version=3&feature=player_detailpage" type="application/x-shockwave-flash" allowfullscreen="true" allowscriptaccess="always" height="180" width="320"></embed></object><br /><span style="font-style: italic;">(From Raydiance Inc)</span><br /><br />To that end, Raydiance's core platform, Smart Light, can simply be adapted (mainly turning down the power) for non-machining applications in defense and security such as remote sensing of hazardous chemicals and LADAR. Dr. Mielke's invited talk will likely emphasize Raydiance's pursuits in these areas since his talk is in the Government and Security subcategory. I will be interested to see what wavelength tuning options, wavelength conversion, or different center wavelengths Raydiance may be investigating for threat detection since Smart Light currently resides in the telecom C-band near 1550 nm and many absorption lines for molecules of interest live in the mid-IR. Until then, I hope you will enjoy, like me, these videos of lasers "vaporizing" material and leaving beautiful designs for very practical applications.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-44477338550900729912011-10-19T21:12:00.000-07:002011-10-21T23:01:37.856-07:00Using Soda Cans to Beat the Diffraction Limit<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdy2UJJ7QJ6H_mSPgsSDXIzKrOhAvS_owDpKAyIQRdoi2_qPKZKHBg4R0k03_iT1kOhgYkhK2db6fb6uZ_XRH9sLdBb13rGRWi5BY5nP-jQHABqQYOVzPNpca7JONXCCONoRfAwbeJI-U/s1600/SodaCans.png"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 377px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdy2UJJ7QJ6H_mSPgsSDXIzKrOhAvS_owDpKAyIQRdoi2_qPKZKHBg4R0k03_iT1kOhgYkhK2db6fb6uZ_XRH9sLdBb13rGRWi5BY5nP-jQHABqQYOVzPNpca7JONXCCONoRfAwbeJI-U/s400/SodaCans.png" alt="" id="BLOGGER_PHOTO_ID_5665436801653582834" border="0" /></a><span style="font-style: italic;font-size:85%;" >(Above: Setup of the metalens (soda cans) used to focus a sound wave to a size of 1/25 th of the wavelength of the waves used to generate the beam)</span><br /><br />Professor Mathias Fink from ESPCI ParisTech and Institut Langevin doesn't fit the typical profile for a plenary speaker at an optics conference, which is precisely why why you won't want to miss his <a href="http://www.cleoconference.org/Home/Program/Plenary-Session.aspx">plenary talk at CLEO 2012</a> this May. Though acoustics is the consistent medium for his work, his research more broadly consists of understanding the nature of waves and how to get around the limits assumed by our conventional understanding, such as diffraction-limited focusing and imaging. Much of professor Fink's work since the late 1990's has been using time-reversal, the subject of his upcoming plenary talk, to achieve these ends.<br /><br />For example, in the <a href="http://prl.aps.org/abstract/PRL/v107/i6/e064301">August 5, 2011 issue of <span style="font-style: italic;">Physical Review Letters</span></a>, Fink and collaborators demonstrated that they could focus a sound wave to 1/25 th of the wavelength of the waves used to create the focused beam. Ironically, this novel feat was obtained using very conventional objects- soda cans and computer speakers.<br /><br />The MacGyveresque experiment shown in the figure above uses a grid of soda cans, a group of subwavelength acoustic resonators, to act as a "<a href="http://prl.aps.org/abstract/PRL/v104/i20/e203901">metalens</a>". When illuminated with a broadband field, this metalens allows subwavelength detail in the near-field to be encoded onto propagating waves. Essentially the metalens is a very good evanescent-to-propagating-wave converter, "unsticking" evanescent waves with subwavelength detail that are typically locked to the surface of the object (or source) of interest. This phenomenon is analogous to the generation of surface plasmons in near-field microscopy (<a href="http://cleoqels2010.blogspot.com/2011/08/year-of-plasmon.html">see the August 16th post below</a>). The propagating waves, now containing subwavelength information, can be detected in the far-field and time-reversed (essentially run backwards) in order to focus to subwavelength spots.<br /><br />Time-reversal essentially amounts to phase-conjugation. However, unlike optical phase conjugation, time-reversal is broadband. Rather, time-reversal is phase conjugation for <span style="font-style: italic;">every frequency</span> at once.<br /><br />In order to experimentally employ time-reversal, one needs a time-reversal mirror (TRM). For an acoustic wave, a TRM is essentially an array of piezoelectric transducers spread over a surface through which the wave of interest propagates. Each transducer records the wave at its unique position and then is made to play back the time-reversed copy such that the each wave retraces its complex path back to the source. Professor Fink and collaborators first demonstrated the power of <a href="http://prl.aps.org/abstract/PRL/v75/i23/p4206_1">time-reversal in the mid 1990's</a> when they focused sound to a much smaller spot size than allowed by the aperture of the transducer array producing it. They discovered that when the source was allowed to scatter many times off of a random array of steel rods, they could reverse the signal such that it came back to a smaller spot size than the original source. The long path lengths from multiple scattering effectively widened the focusing aperture. When they removed the steel rods, they could only focus to the predicted size limited by the aperture of the transducer array.<br /><br />In a <a href="http://physicstoday.org/resource/1/phtoad/v50/i3/p34_s1?isAuthorized=no">1997 physics today article</a>, Fink explains time-reversal using an analogy of an exploding block:<br /><br />"If we want to reconstruct an exploded block from the various scattered pieces, a time-reversal mirror would be a device that precisely reverses the velocity of each debris particle as it crosses a closed surface surrounding the initial block. But before being sent back, each particle must be held for an appropriate delay time: To reconstitute the block, one has to send back first the slowest pieces, which had arrived last."<br /><br />Time-reversing an exploding block is of course thermodynamically impossible, however, for waves which can be described completely by a limited amount of information, it is reality. The strangeness of the multiple scattering experiment performed by Fink <span style="font-style: italic;">et al</span> in the 1990's, and current experiments, is that it is as if the exploding block is being time-reversed to be put back together into a block that is smaller than the original.<br /><br />So what about time-reversal for optics? Subdiffraction focusing and imaging in the optical domain have already been shown using a variety of techniques without time-reversal (for example, see <a href="http://paramountistcleo2011.blogspot.com/2011/09/zoo-of-super-resolution-microscopy.html">Frank Kuo's September 10th post</a>). However, two recent articles by <a href="http://www.nature.com/ncomms/journal/v2/n8/abs/ncomms1434.html">McCabe <span style="font-style: italic;">et al</span></a>, and <a href="http://www.nature.com/nphoton/journal/v4/n5/abs/nphoton.2010.3.html">Vellekoop <span style="font-style: italic;">et al</span></a> show the optical analog of Fink's 1990's work, in which a highly scattering medium combined with time-reversal (via spatial light modulators) can be used to enhance an optical focus. Another recent work by <a href="http://www.nature.com/nphoton/journal/v5/n3/abs/nphoton.2010.306.html">Xu <span style="font-style: italic;">et al </span></a>from Washington University shows a technique called Time-Reversed Ultrasonically Encoded (TRUE) focusing in which only the encoded portion of light from a microscope focal volume is time-reversed back to the sample for clean focusing. In this case the time-reversal mirror consists a holographic technique using a photorefractive crystal to a phase-conjugate of the right bit of light back to the focus.<br /><br />I'm not only looking forward to Fink's plenary talk to learn about other uses of time-reversal in optics, but to generate ideas of what other wave phenomena may be borrowed from fields like acoustics, microwave communication, and quantum mechanics and visa-versa. After all, it's just the same wave equation.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-39169364031134941692011-10-02T22:53:00.000-07:002011-10-02T23:12:37.824-07:00Call for PapersOctober 1, marked the official call for papers for <a href="http://www.cleoconference.org/home.aspx">CLEO 2012</a> in San Jose, CA. I've decided to include a recurring gimmick in my past blog submissions for CLEO- a countdown clock. Mark your calendars for December 5, for submitting contributed work- there is still a good 63 days left to collect good data, put finishing touches on new instruments, or simulate new phenomena.<br /><br />The <a href="http://www.cleoconference.org/home.aspx">official CLEO website</a> has already posted <a href="http://www.cleoconference.org/Home/Program/Plenary-Session.aspx">plenary speakers</a>. You can visit <a href="http://www.expocadweb.com/cleo12/ec/forms/attendee/indexTab.aspx">Expocad</a> which will take you through the expo map, giving you booth information as you hover your mouse over different areas of the map. Stay tuned to this blog and CLEO's other various social media in the lower right-hand corner of the main page for the latest information for authors, attendees, speakers, students, and exhibitors.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com1tag:blogger.com,1999:blog-8860229920122250605.post-49091669321361109712011-09-30T19:01:00.000-07:002011-10-18T21:58:51.602-07:00Photonics for Global Health<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyx4ZiK2TC5q-KO8zrIhD7wF9GCS9xtnAGU9dRnzpJNJ_zJAGITkra5y0ZBSBphLVLGBSpc7rJfISSZ0Pl3uBN6BMs6mt2sKbs40MBSjGDMnJSiYuwW6tIigaH74OKYuSBLGIU0rM2l88/s1600/Skin.png"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 305px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyx4ZiK2TC5q-KO8zrIhD7wF9GCS9xtnAGU9dRnzpJNJ_zJAGITkra5y0ZBSBphLVLGBSpc7rJfISSZ0Pl3uBN6BMs6mt2sKbs40MBSjGDMnJSiYuwW6tIigaH74OKYuSBLGIU0rM2l88/s400/Skin.png" alt="" id="BLOGGER_PHOTO_ID_5665062582586029714" border="0" /></a><span style="font-size:85%;">(Left: Reflection images of a histopathology slide corresponding to skin tissue using a low-cost, portable, lens-free off-axis holographic microscope. Right: Conventional reflection-mode microscope image of the same specimen using a 4X objective lens (NA: 0.1). Image from <a href="http://www.opticsinfobase.org/boe/abstract.cfm?uri=boe-2-9-2721"><span style="font-style: italic;">Biomedical Optics Express</span></a>)</span><br /><br />Research performed in the <a href="http://innovate.ee.ucla.edu/welcome.html">Ozcan group</a> at UCLA holds a unique place in the field of optics and photonics. Besides the typical pursuit of advancing optical technology, another major initiative of this photonics group is solving problems of global world health, particularly in resource-poor countries.<br /><br />Early September marked a milestone for the UCLA group as they published work on a compact, low-cost (~$100 USD of parts), dual-mode microscope with 2 micron resolution in <a href="http://www.opticsinfobase.org/boe/abstract.cfm?uri=boe-2-9-2721"><span style="font-style: italic;">Biomedical Optics Express</span></a> (also written up in a recent <a href="http://www.osa.org/About_Osa/Newsroom/News_Releases/Releases/08.2011/Microscope-on-the-Go.aspx">OSA press release</a>). The key to making such a low-footprint, low-cost, lab-grade device is using holographic microscopy. The image information stored in a hologram (the interference of the reflected or transmitted light from the specimen with a reference beam) requires no lenses, drastically reducing the weight, size, and overall expense of the device. A computer reconstructs the wavefront reflecting from (or transmitting through) the sample instead of a lens (see fig below). The impact to world health will be increased blood-diagnostics, water quality tests, tissue screening and analysis, and other imaging diagnostics in areas where microscopes currently are not available due to cost and/or remoteness of location. Getting more microscopes into the hands of health workers may have large impacts for heading off disease outbreaks as well as treatments for individuals.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiH9Isen7Ja1gQmoDNvXsxvXbp-gbUrCXcHRVcYB6UVBmD-ze9VIC8o7o3sCsKl7vGKd96Nvc37C9OL9eZOGlvNyBCoOccYlHVkDZQQrD1ZiTFPXAiCEnzl5kHvYJF1u8UsKlinaSCihk4/s1600/Microscope.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 291px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiH9Isen7Ja1gQmoDNvXsxvXbp-gbUrCXcHRVcYB6UVBmD-ze9VIC8o7o3sCsKl7vGKd96Nvc37C9OL9eZOGlvNyBCoOccYlHVkDZQQrD1ZiTFPXAiCEnzl5kHvYJF1u8UsKlinaSCihk4/s400/Microscope.jpg" alt="" id="BLOGGER_PHOTO_ID_5658626018792524274" border="0" /></a><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><span style="font-size:85%;">(Schematic of the 200 gram microscope developed by the Ozcan group in reflection mode. LD: laser diode, PH: pin hole, BC: Beamsplitting Cube. Note the two AA batteries as the power source as well as for scale. Image from M. Lee, O. Yaglidere, and A. Ozcan, <span style="font-style: italic;">Biomedical Optics Express</span>, 2, 2721 (2011). </span><span style="font-size:85%;">)</span><br /><br />The idea of using holograms in microscopy is not new. In fact it was the quest for higher resolution in electron microscopy which prompted Dennis Gabor to devise wavefront reconstruction by holography in 1948. Gabor coined the word "hologram" which translates "whole message" to emphasize the amount of information that is stored in this very special interference pattern. For a brief history of holography from its roots in microscopy, its development through radar, and its boom in mainstream art and media in the 60's and 70's , see Jeff Hecht's <a href="http://www.osa-opn.org/Archives/0710/Features/Holography-and-the-Laser.aspx">2010 OPN article</a>.<br /><br />What makes the Ozcan group's work so special is not the use of a fundamentally new technique, but clever and impressive engineering. This holographic microscope is small, inexpensive, and can work in both transmission and reflection mode. The transmission mode of the current device is similar to an earlier work by the Ozcan group- a cell-phone microscope. In the summer of 2010, the UCLA group published work in <a href="http://pubs.rsc.org/en/Content/ArticleLanding/2010/LC/C003477K"><span style="font-style: italic;">Lab on a Chip</span></a> demonstrating a clever attachment to an ordinary cell-phone which could convert it into lab-grade microscope (see the youtube short below). By employing digital holographic microscopy, the group was able to produce a 38 gram attachment without any lenses, lasers, or bulky optics, which when incorporated with the cell phone camera, produced hologram on the cell phone detector array. The idea is that the hologram data would be sent over the same cell phone to the closest hospital/analysis station, a computer would process the hologram to extract the image information, and then the image would be sent back to the same phone, all within seconds of placing the sample to be analyzed into the device.<br /><br /><object width="432" height="244"><param name="movie" value="http://www.youtube.com/v/VH5H6uSQUFE&hl=en_US&feature=player_embedded&version=3"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always"><embed src="http://www.youtube.com/v/VH5H6uSQUFE&hl=en_US&feature=player_embedded&version=3" type="application/x-shockwave-flash" allowfullscreen="true" allowscriptaccess="always" width="432" height="244"></embed></object><br /><br />Though the current device cannot be so easily integrated onto a phone, the additional benefit of reflection-mode operation makes up for its "bulkiness." By operating in reflection-mode, the new microscope is additionally suited for imaging optically dense media like tissue, something not possible using in-line transmission holography due to spatial distortions in the reference wave. The developers decided to keep a transmission-mode an option, however, since it produces a larger field-of-view then its reflection counter-part and is easier to align and operate.<br /><br />Once again a computer is needed to reconstruct the image from the hologram. However, hologram data could be sent to the nearest processing center if the field-worker is not carrying a laptop already. My thoughts immediately lead to the computer produced by Quanta through the <a href="http://one.laptop.org/">One Laptop per Child</a> initiative (OLPC). The XO laptop costs approximately $200 and can run on power sources such as solar, human power, generators, wind or water power. Though the aim of OLPC is to close the digital gap for children of resource-poor nations, I wonder if an XO equivalent could be developed to bridge the gap in digital medicine, not just on a records basis, but for data acquisition and processing for field-portable medical instruments like the microscope produced by the Ozcan group. I can imagine this $100 microscope interfaced with a $200 laptop.<br /><br />What is exciting about this work is that it underscores the beauty and power of cross-discipline connections. Though lensless holographic microscopy is not new, using it as the foundation for a low-cost, field-portable devices is. To learn about more innovations like these, be sure to visit sessions this spring at <a href="http://www.cleoconference.org/home/Submit-Papers/Topic-Categories.aspx#at1">CLEO Applications and Technology: Biomedical</a> (just in its second year) in San Jose.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com3tag:blogger.com,1999:blog-8860229920122250605.post-64559780291038278612011-08-16T13:20:00.000-07:002011-08-17T09:59:34.653-07:00Year of the Plasmon<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjidtDTLkhf1PJwub2dH6ENuHkWZGOPj9iUQCKcv_tafGH6TVoutD58emA3jZ1nTW3ImmlepR-gyy0F9v0658HFmcDc0E-JCjgEBT88vhUeln2sKuY4rapQ3sAARWwBDI_s6qrn7G6Dd4M/s1600/naturematcover.gif"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 243px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjidtDTLkhf1PJwub2dH6ENuHkWZGOPj9iUQCKcv_tafGH6TVoutD58emA3jZ1nTW3ImmlepR-gyy0F9v0658HFmcDc0E-JCjgEBT88vhUeln2sKuY4rapQ3sAARWwBDI_s6qrn7G6Dd4M/s320/naturematcover.gif" alt="" id="BLOGGER_PHOTO_ID_5641856571450541682" border="0" /></a><span style="font-size:85%;"><span style="font-style: italic;">(Left: August Cover of Nature Materials sh</span></span><span style="font-size:85%;"><span style="font-style: italic;">owing Liu et al s work on gas sensing using plasmonic response from a triangular nanoantenna. The work in the Nature article was expanded from that </span></span><span style="font-size:85%;"><span style="font-style: italic;">presented in CLEO 2011, postdeadline session)</span></span>
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<br />This year may not be a flush for the market but it is looking good for plasmonics. Expansion of the the work shown in CLEO 2011, Postdeadline paper "Nanoantenna-enhanced gas sensing in a single tailored nanofocus," from Na Liu<span style="font-style: italic;"> et al.</span> just took the August cover of <span style="font-style: italic;">Nature Materials</span> (see the figure above). Additionally, plasmonics has had a solid recent run of the main-stream physics circuit after the publication of two <span style="font-style: italic;">Physics Today</span> articles earlier this year in February and July.
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<br />The July issue of <span style="font-style: italic;">Physics </span><span style="font-style: italic;">Today </span>features an article by Lukas Novotny from University of Rochester in which he reviews near-field optics, the broader category where plasmonics resides. Earlier in the year, Mark Stockman of Georgia State University wrote a very accessible and informative article on nanoplasmonics that took the cover of the February issue of <span style="font-style: italic;">Physics Today</span>. The cover shows a 13th century stained glass window of Sainte Chappelle in Paris whose yellow and red brilliance are assumed to come from nanoplasmonic resonances of silver and gold nanoparticles in the glass. The optical effect of how the red changes over the length of the window is said to have purposely been designed to mimic the flowing blood of Christ.
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<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGzEt6Nbtta0kAmGtqY0LBAV__x7oFliVxa4oEtaMahD9GXbthtCGfk1gvKxPMVqtwuNKg0ZoFoeZbdc7mf9LAZnsdqX4xde17hbK5abKlwKlURLHEXPvbzDwoZrig2zQg7EBWLg8HOzk/s1600/nearfield.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 210px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGzEt6Nbtta0kAmGtqY0LBAV__x7oFliVxa4oEtaMahD9GXbthtCGfk1gvKxPMVqtwuNKg0ZoFoeZbdc7mf9LAZnsdqX4xde17hbK5abKlwKlURLHEXPvbzDwoZrig2zQg7EBWLg8HOzk/s400/nearfield.jpg" alt="" id="BLOGGER_PHOTO_ID_5641868723927373346" border="0" /></a>
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<br />(Above: Sketch of Edward Synge's pr</span></span><span style="font-size:85%;"><span style="font-style: italic;">oposed near-field microscope. The red dot denotes the gold nanoparticle. Picture from L. Novotny, Phys. Today, <span style="font-weight: bold;">64</span>, 47 (2011))</span></span>
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<br />Novotny's July article also offers a romantic insight into the history of near-field optics and plasmonics. Novotny, recounts how in 1928, Edward Synge wrote a "prophetic letter" to Einstein proposing a near-field microscope (see Figure above) to optically image a biological sample below the diffraction limit. Synge's proposed microscope, which could not be realized until 1982 (by Dieter Phol's group at IBM of Switzerland), looks eerily familiar to current techniques used for the development of plasmonic devices and sensing- the use of metallic nanoparticles to generate surface plasmons in order to enhance a probing optical field. The two <span style="font-style: italic;">Physics Today</span> articles are must-reads for those who need a crash-course on plasmonics.
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<br />A plasmon is created when the electrons on a metal surface are periodically displaced with respect to the lattice ions by an external, driving, optical field, creating an "electron oscillator." The frequency of the surface plasmon depends not on the driving field, but instead upon the restoring force and effective mass of the electrons in the metal. Changing the size and geometry of the metal structure will alter the restoring force and thereby the plasmon frequency. Using metallic nanostructures of the right size (smaller than the skin depth of the metal but bigger than the distance an electron moves during on optical cycle, 2-20 nm) the electric field due to the plasmon becomes highly localized in the immediate vicinity of the outer surface of the nanostructure (see the Figure below). By coupling the surface plasmon to propagating optical radiation, nanoscale information from the plasmon can be encoded micron-sized optical waves as it is in near-field microscopy. The highly localized field can also be used for a number of sensing techniques like <a href="http://cleoqels2010.blogspot.com/2010/05/jury-duty-and-sers-spectroscopy.html">SERS</a> by which the interaction of a probe beam with a molecule is significantly enhanced due to the presence of nearby nanostructures. The cover article from <span style="font-style: italic;">Nature Materials</span> uses a standard plasmonics approach by using redshifted plasmon response itself from a gold triangle structure for ultra-sensitive detection of hydrogen.
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<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz8f9kxqbdvM2Ftv4osjZQupuRTX7CH5D441OO2ARLPVzoUUue9dpgrJX0iAB_EzAtTx6RPjL722K_43lWymTOgT84AyV6p68m3Ht0dwsdU3SddqkMljKVC71RA-85kD-9BCfL7Mhq-gc/s1600/plasmon.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 206px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz8f9kxqbdvM2Ftv4osjZQupuRTX7CH5D441OO2ARLPVzoUUue9dpgrJX0iAB_EzAtTx6RPjL722K_43lWymTOgT84AyV6p68m3Ht0dwsdU3SddqkMljKVC71RA-85kD-9BCfL7Mhq-gc/s400/plasmon.jpg" alt="" id="BLOGGER_PHOTO_ID_5641868537587184722" border="0" /></a>
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<br />(Above: Diagram of plasmon dynamics on a 10 nm silver nanosphere. Eo represents the external light field, the black arrows represent the electric field from displaced electrons, the plasmon field, and the red arrows show the field inside the sphere. Picture from M. Stockman, Phys. Today, <span style="font-weight: bold;">64</span>, 39 (2011) </span></span><span style="font-size:85%;"><span style="font-style: italic;">)</span></span>
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<br />The exciting field of plasmonics has applications and positive repercussions in other fields as well. Tumor cells have been found to readily take up nanoparticles. By illuminating tissues with non-lethal IR light, the heat generated from enhanced local-fields of the high-Q nanostructures selectively kills cancer cells. Plasmon-enhanced solar energy conversion entails using metallic structures to better localize light for solar concentration. The opening tutorial, "Solar Energy Applications of Plasmonics," by Professor Harry Atwater of Caltech in CLEO:QELS session "Frontier Applications of Plasmoincs" during CLEO 2011, addressed this burgeoning new field.
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<br />There is no doubt that CLEO 2012 will host a number of technical and invited talks, both fundamental and applied, on the subject of plasmonics. After reading the <span style="font-style: italic;">Physics Today</span> articles, I think I will have to add a lecture or two on plasmonics in my junior-level E&M class this fall. I will definitely have to attend some plasmonic talks next CLEO to learn more about this extremely interesting work that saddles fundamental physics and cutting-edge applications.
<br />Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-62252091300682391842011-07-12T19:38:00.000-07:002011-07-14T10:11:25.773-07:00Are we Entering a Solar Boom?<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://i.i.com.com/cnwk.1d/i/bto/20091221/FirstSolarNRG_610x505.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 331px;" src="http://i.i.com.com/cnwk.1d/i/bto/20091221/FirstSolarNRG_610x505.jpg" alt="" border="0" /></a><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><span style="font-style: italic;"><span style="font-size:85%;">(First Solar employees working on the 21 MW solar power station in Blythe, CA in the Mojave Desert. The project was completed in December 2009. Photo from cnet News; originally from First Solar. First Solar just received $4.5 billion in DOE loans to build three new stations in the Mojave Desert whose total output will be 1.33 GW)</span></span><br /><br />This summer seems to be marked by a frenzy of solar energy initiatives and development. The <span style="font-style: italic;">Business News</span> section in the May issue of <span style="font-style: italic;">Nature Photonics</span> reported on four recent major investments in solar technology manufacturing: <a href="http://www.jasolar.com/">JA Solar</a> of Shanghai plans to build a 3 GW capacity plant in Hefei, China for the manufacturing of monocrystalline silicon solar cells. Investors have pledged $2.05 billion over the next four years, and production is slated to begin in 2012. Polysilicon Technology Company, a joint venture between Mutajadedah Energy of Saudi Arabia, and KCC Corporation of Seoul will build a $1.5 billion facility to produce solar-grade polysilicon in Jubail, Saudi Arabia by 2017. The Indian government is discussing a joint venture with nanotech company, Rusanano, of Moscow to obtain a consistent supply of silicon for Indian photovoltaic manufacturers with hopes of obtaining 2,000 tons of silicon ingots for solar cell production. And <a href="http://www.solopower.com/index.html">SoloPower</a> of San Jose was guaranteed $197 million from the U.S. Department of Energy (DOE) to build a plant in Oregon for the manufacturing of flexible copper-indium-gallium diselenide (CIGS) for light-weight solar panels.<br /><br />Though CIGS are not as efficient as crystalline silicon, like other thin-film technologies they reap benefits of<a href="http://www.eere.energy.gov/basics/renewable_energy/polycrystalline_thin_film.html"> inexpensive fabrication and production</a> when compared to silicon cells. CIGS need only a fraction of the material to absorb incident photons. They can be manufactured in large-area, automated processes unlike more time-intensive and expensive ingot growth used for silicon. The flexible thin-film technology allows SoloPower's CIGS panels to be 75% lighter than traditional panels for less expensive and more practical installation on industrial roof-tops.<br /><br />The DOE made even bigger news for solar energy investment, however, at the end of June when it <a href="http://www.energy.gov/news/10404.htm">promised $4.5 billion</a> for the construction of three different California photovoltaic power plants: <a href="http://www.avsolarranchone.com/index.php">Antelope Valley Solar Ranch 1</a>, the <a href="http://www.blm.gov/ca/st/en/prog/energy/fasttrack/First.html">Desert Sunlight Project</a>, and the <a href="http://www.topazsolar.com/index.php">Topaz Solar Project</a>. Arizona-based company <a href="http://www.firstsolar.com/en/index.php">First Solar, Inc</a> will sponsor all three projects, constructing each solar array with cadmium telluride (CdTe), thin-film photovoltaic modules. Together, the new power plants will provide 1.33 GW (powering the equivalent 275,000 U.S. homes) and offset the generation of 1.8 megatons of carbon dioxide. As described by Alexis Madrigal, author of "Powering the Dream: The History and Promise of Green Technology," (Da Capo Press, 2011), in a <a href="http://www.sciencefriday.com/program/archives/201106173">June 17, interview on NPR's Science Friday</a>, the Mojave Desert solar plants will prove to be particularly effective when compared to other green initiatives. One reason for their effectiveness is their location- the solar plants will be simultaneously near large population centers, L.A. and Las Vegas, with ideal conditions for sunshine- the desert. This is in contrast to wind energy where ideal locations for wind farms often correspond to areas with low population densities (like the plains of North Dakota) and so power distribution becomes an issue. Additionally, the sunlight in the desert suits itself to matching peak output of the solar grid with peak usage- as everyone cranks up the air conditioning at the hottest time of the day, the PV modules are cranking out the most amps.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtx3lN8zOm9tiV-TXsosuhTCcvLr3K2nmgS3kYgs2vK2NRkPvHzRcPn95v9E7rvI9sscze0_Yv0NjVc6WccLBB0VX78YzKegGw-fYiIYCt2rkKX7vrKjWGyYKG26xAHIDX8ioSEWaCCkI/s1600/PVeff.png"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 400px; height: 273px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtx3lN8zOm9tiV-TXsosuhTCcvLr3K2nmgS3kYgs2vK2NRkPvHzRcPn95v9E7rvI9sscze0_Yv0NjVc6WccLBB0VX78YzKegGw-fYiIYCt2rkKX7vrKjWGyYKG26xAHIDX8ioSEWaCCkI/s400/PVeff.png" alt="" id="BLOGGER_PHOTO_ID_5629108162523039314" border="0" /></a><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><span style="font-style: italic;"><span style="font-size:85%;">(Time-line of photovoltaic efficiencies for various cell types; from the National Renewable Energy Lab)</span></span><br /><br />The choice of thin-film CdTe for the solar cells is once again due to balancing cost and efficiency. First Solar claims that its CdTe modules have the smallest carbon footprint (this includes fabrication and recycling of the module over its lifetime) compared to any photovoltaic on the market, as well as the fastest energy payback time (EPBT). They also note that the high temperature coefficient of CdTe allows their modules to perform better than silicon at higher temperatures, which will obviously be crucial given the heat conditions of the Mojave.<br /><br />Other summer solar news include McGraw-Hill's June 13, announcement to build the world's largest private solar plant at its East Windsor, New Jersey campus. Though New Jersey is not as sunny as the Mojave Desert, the plant is slated to generate an impressive14 MW.<br /><br />A detailed <a href="http://nycsolarmap.com/">solar map</a> was released by the City University of New York on June 16, which shows the solar energy production potential of the New York City's rooftops. The <span style="font-style: italic;">New York Times</span> reported that the solar map, made by making LIDAR sweeps the previous year, shows that two-thirds of New York's rooftops have great potential for solar harvesting. If these rooftops were covered with solar panels, the city could use them to meet half of its electrical power consumption needs, even at peak use.<br /><br />NYC roofs were not the only ones in the solar lime-light recently. Google announced on June 14, a partnership with <a href="http://www.solarcity.com/default.aspx">SolarCity</a> in which they will provide a $280 million fund to help finance SolarCity's solar panel leasing program for rooftops across the U.S. The largest hurdle for residential solar panels is the up-front cost and installation of panels, typically tens of thousands of dollars. By bankrolling SolarCity's leasing program, Google will put solar panels on the roofs of more U.S. homes. Other U.S. companies with solar leasing programs include <a href="http://www.sungevity.com/">Sungevity</a> and <a href="http://www.sunrunhome.com/">SunRun</a>.<br /><br />In more solar news, <a href="http://www.prnewswire.com/news-releases/solar-photovoltaics-gaining-momentum-and-poised-to-challenge-fossil-fuels-say-ieee-solar-experts-123904389.html">IEEE released a statement</a> on June 15, projecting that solar power could become the most economical form of energy generation in the next 10 years, provided a continued increase in efficiency of photovoltaics and development in mass production of of solar cells.<br /><br />To that aim, a <a href="http://www.nature.com/nphoton/journal/v5/n7/full/nphoton.2011.137.html">collaboration between Japan’s New Energy and Industrial Technology Development Organization (NEDO) and the European Commission</a>, which began June 1, 2011 will attempt to push PV efficiency to greater than 45% in the next four years. The record is currently just over 40% in concentrator, multi-junction devices made by companies like Sharp, Spectrolabs, Spire and Solar Junction (see efficiency curve above). To meet this goal, the Japanese-EU collaboration led by Antonio Luque of University of Madrid and Masafumi Yamaguchi of Toyota Technological Institute will pursue an approach using multi-junction cells, but will also explore options of adding nanostructures like quantum wells or quantum dots. They will also try to enhance the design of typical solar module concentrator optics.<br /><br />The potential solar boom will not only be good for our planet but will provide the optics community with new challenges and opportunities in R&D. If investment in solar energy continues at its current pace, we could see a significant shift in the funding and direction of optics research. Whatever the shape or face of the next best efficient or cost-effective solar cell, be rest assured you will hear about it at CLEO.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com4tag:blogger.com,1999:blog-8860229920122250605.post-84857499875765244412011-05-11T21:38:00.000-07:002011-05-13T20:06:02.544-07:00Capitol Hill Day<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioP3ODThKKUkwAAR_2h3Ho1K4R_a96z19BH98rxHaHQ10pFqt9pRfywVzXDKK9glne5qemYMOo7dNnPjKQFf650zwFkbx1mFDPnJfHLXZ3rARm_w3d55CpGvXr5FGTdS5KyRHvLnp2y3g/s1600/CapitolHill1.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 311px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioP3ODThKKUkwAAR_2h3Ho1K4R_a96z19BH98rxHaHQ10pFqt9pRfywVzXDKK9glne5qemYMOo7dNnPjKQFf650zwFkbx1mFDPnJfHLXZ3rARm_w3d55CpGvXr5FGTdS5KyRHvLnp2y3g/s320/CapitolHill1.jpg" alt="" id="BLOGGER_PHOTO_ID_5605717727895485026" border="0" /></a><br /><span style="font-style: italic;"><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />(From Left: Laura Kolton (OSA Public Policy Team), Greg Quarles (President of B.E. Meyers Electro Optics), James van Howe (Assistant Professor, Augustana College), Representative Bobby Schilling (IL), Adam Zysk (research associate IIT, Chicago), Hong-Jhang Syu (Research Assistant, National Taiwan University))</span><br /><br />On Thursday May 5th, a number of the conference attendees took a bus to Washington D.C. to visit the offices of various members of congress and senators of our respective legislative districts and states. Our goal was to help defend science funding levels in the wake of strong national sentiment to reduce U.S. federal spending.<br /><br />What we learned the night before in the briefing at the Baltimore Convention Center was fascinating, and the actual day of visiting policy-makers to discuss science-funding issues was exhilarating. In the briefing, we learned that one of most effective ways of influencing a senator or member of congress was through a conversation with a constituent. Visits from lobbyists actually rank much lower on survey data from congressional staffers. What was also fascinating to me was that an <span style="font-style: italic;">email</span> from a constituent ranked just below a <span style="font-style: italic;">visit</span> from a constituent and still far above a visit from a lobbyist. I immediately promised myself to regularly send email to my representatives and you should too! It works!<br /><br />At the briefing, one of the speakers, Mike Lubell, the Public Affairs Director at the American Physical Society, showed us revealing survey data from focus groups. One group was from a community with many ties to science industry and one had very little. Shockingly, the results were the roughly the same for each:<br /><br />1. The groups generally loved science and are supportive of science research<br />2. The groups thought that science should be a national priority<br />3. Here's the kicker: The the groups were distrusting of the federal government as the funding source for science research. Somehow they want to keep good science without federal funding.<br /><br />So there is good and bad news. Scientist can expect good moral and emotional support from the public, but maybe not dollars. In fact, Lubell showed a list that had science as the second most chosen category from the groups of where to cut federal funding.<br /><br />Our task for the Capitol Hill visits was well laid out- try to educate our representatives about the role of federal money in science research; how it is almost the sole source for science funding in the U.S., how science requires sustained funding over time for results, and how our quality of life is enhanced by the technology we develop such as noninvasive biomedical imaging techniques for cancer diagnostics and photovoltaics for green energy production, not to mention the highly skilled workforce good science creates.<br /><br />I particularly liked Lubell's list of "good" and "bad" words and phrases to bring up or avoid as you are trying to convince non-scientists of the importance of federal funding for science. Words like "basic research" and "fundamental research" did note bode well in the public eye. They took "basic" and "fundamental" to mean "remedial." The phrase, "Investing in America's future," tracks well with Democrats, but not Republicans since "investment" to the GOP means "spending." There was a fairly strong equal distaste among different parties for the idea that America needs to be the top competitor among foreign nations in science. I guess our Cold War attitude as been slipping since Reagan administration. A "good" party-neutral phrase is the cheesy (sorry but it is), "Building a better America." The list goes on and is both entertaining and illuminating as to the perception of science in the U.S.<br /><br />Because I live in Iowa but work in Illinois, I met a handful of staffers from both states. From the picture above, you can see that my team was able to personally meet congressman Bobby Schilling (R) from Illinois. Congressman Schilling was extremely kind and hospitable, as were the staffers from the other offices we visited: Senator Kirk (R-IL), Senator Grassley (R-IA), Congressman Quigley (D-IL), and Congressman Braley (D-IA). I was very impressed with the professionalism and cordiality of the young staffers who took the time to listen to our concerns.<br /><br />So I know you are now asking yourself, "What can I do to help?" Begin by emailing your representatives with your concerns for science funding (at the Capitol Hill visits we were advocating <span style="font-weight: bold;">sustained</span> levels (not an increase) . Also be sure to visit the <a href="http://www.osa.org/about_osa/public_policy/default.aspx">OSA public policy homepage</a> for updates on additional organized Capitol Hill visits, pending science-bearing legislation, letters to sign, etc.<br /><br />For more info and photos on the Capitol Hill day event <a href="http://www.osa.org/About_Osa/Public_Policy/Policy_Programs_Events/Capitol_Hill_Visits/CHD_2011/default.aspx">click here</a>.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-75336207150069042922011-05-08T22:35:00.000-07:002011-05-08T22:38:07.323-07:00See you in San Jose!I hope this post greets everyone safe and cozy at home, resting from a week packed of optics innovation. I am still catching my breath. There was just so much. I would have liked to have attended many more talks, visited more booths at the expo, met up with more colleagues, and posted more (I still might on the latter- it turns out, for better or worse, Newton's First Law applies to blogs as well). Harold Metcalf was correct is is pre-CLEO analysis "Looking over the program and the titles of the sessions, I feel like a kid in a candy store- with unlimited funds, but limited time. It's impossible to do everything."<br /><br />However, I intend to update this ClEO blog for a little longer with posts that I couldn't squeeze in during the week. I am going to try to have my "candy" and eat it too, though hopefully without a stomachache (figuratively or literally) for blogger or reader.<br /><br />Regardless, mark your calendars for May 6-11, in 2012 for next year's meeting in San Jose!Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-27721613110789749192011-05-07T19:16:00.000-07:002011-05-08T22:49:39.229-07:00Time-Lens 2.0Brian Kolner and Moshe Nazarathy coined the word "time-lens" in 1989 after using one to compress a pulse. They made a system in the time-domain that was a complete analog to a lens system in space. Their time-lens took a fat pulse and "focused" it, just like a spatial lens could take a fat beam and focus it to a smaller size. For more details, see <a href="http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel1%2F3%2F7447%2F00301659.pdf%3Farnumber%3D301659&authDecision=-203">Kolner's well-written 1994 review</a> on space-time duality and <a href="http://www.opticsinfobase.org/abstract.cfm?uri=JLT-24-7-2649">van Howe and Xu's 2006 review </a>on temporal-imaging devices).<br /><br />Because much of my thesis work focused (pun intended) on temporal-imaging devices, I can't help seeing them everywhere. This year's CLEO conference was no exception with some talks being more direct about it than others.<br /><br />Takahide Sakamoto from the National Institute of Information and Communication, in Tokoyo, Japan discussed time-lenses without using the word itself in tutorial, <span style="font-weight: bold;">CMBB1</span>, in "Optical Comb and Pulse Generation from CW Light." Sakamoto showed impressive work on comb synthesis from CW light using electro-optic (EO) modulation. He demonstrated that EO phase modulation provides the most efficient way to move from CW light to the picosecond bandwidth regime. Higher order nonlinearities like chi-3 from fiber (EO is chi-2 process) can then be used to move bandwidth to femtosecond regime. Sakamoto stressed a clever biasing and driving technique using an itensity modulator that allowed truly flat comb spectra.<br /><br />Other work leveraging temporal imaging concepts were <b>CMD1</b>, "Tunable high-energy soliton pulse generation from a large-mode-area fiber pumped by a picosecond time-lens source," from Chris Xu's group at Cornell University and <b>JTuI77</b>, "Scalable 1.28-Tb/s Transmultiplexer Using a Time Lens" by Petrillo and Foster. The former used electro-optic modulation as the time-lens to generate a seed source from CW light for solition shifting. The latter used four-wave mixing as the time-lens mechanism in order to look at the Fourier transform of a data packet for high-speed time-division multiplexing to wavelength-division multiplexing conversion (just as a spatial lens can provide a Fourier transform of a spatial profile, a time-lens can give the power spectrum of a temporal profile). Note that the Xu group has also developed <a href="http://www.opticsinfobase.org/abstract.cfm?uri=oe-18-23-24019">time-lens source for CARS microscopy</a>.<br /><br />Work from Andrew Weiner's group also made use of time-lenes, <b>CWN3</b>, "Broadband, Spectrally Flat Frequency Combs and Short Pulse Sources from Phase modulated CW: Bandwidth Scaling and Flatness Enhancement using Cascaded FWM" and <b>CFG6</b>, "Microwave Photonic Filters with > 65-dB Sidelobe Suppression Using Directly Generated Broadband, Quasi–Gaussian Shaped Optical Frequency Combs." These works used a front end similar to those shown by Sakamoto, but then added an assisted nonlinear enhancement to bandwidth by using four-wave mixing.<br /><br />Finally, former CLEO Blogger, <a href="http://ksenia-at-cleo2010.blogspot.com/">Kesnia Dolgaleva</a>, authored <b>CThHH6</b>, "Integrated Temporal Fourier Transformer Based on Chirped Bragg Grating Waveguides" to show a compact, integrated Fourier Transformer, which though not a time-lens, is another device similarly based on space-time duality. This paper draws upon co-author Jose Azana's previous fiber Bragg grating work, which is just one of many Azana's contributions to the field of temporal imaging.<br /><br />If you look hard enough, you can see time-lenses anywhere- all you need is a device that gives a quadratic phase in time to an optical wavefront (nonlinear frequency mixing, used everywhere in optics, is one technique that works well). However, the big advantage for recognizing a time-lens when you have one is that you can bring all of the knowledge of spatial imaging systems to your work with a simple change of variables.<br /><a></a>Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com1tag:blogger.com,1999:blog-8860229920122250605.post-54115232876396015622011-05-05T20:41:00.001-07:002011-05-06T00:04:51.423-07:00The Real-Life Tony Stark<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" 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1Lmep0HL1Wl8MYui5r24kGrlaQxjoAyn7rxxtcCZsY6giU9xvYxwyaNyR+HbWk0wGP8A9ME5T1DM0lp7SR0hUuLY5htma7mCC13SCCtPg9iUXVKVNlao11WoKeYhlRrZPvuY0A5fzd7wQpvE+y62GG7xIbXpBwLcRTkwIALcxEtBEWNrCCqqNclpZlJen+jDNpudJkcADjJAtma2wOplwsO50BULGzI5mw8yQjsXRaPccHNJIB0da8Ob1upthYPPUdMQBHq7TztKaZpVVldiKeV2UxLbGPNQlEY901Xnq436wY5IdSQIQuYYSwpsHwnNGlx59UEJblgzZpptbvGlhdxZjPu6AAfXyQ1YZu8I6hiw8yTm87qSps4EVHizWMLj5yGgT3JVN7NyitNFRhCW1GnmHNPwIXoAqLGbPwLn1GkDhzCTy1Fu5WyICs9jBkq9h29SbxMICSFFlKF3iQvSGE2FFhQ/MmlyYUhRZNC5lybK5Fgd7QOiTfSrkeG3/dKkb4bf91J0ZPYvqiUW9HRZzG4k4isGsktFmDqTq6O5+ULTeL8GcPQvZ1Q5R1gCXH4QPzLKbFxxoVW1Bq0yFapRVvkbjSk7NZiMUMJRota0OqtlzzUbmDSfs0/u2m41lZfGPfWcSAZu4iR5mOvktV/xRmMqE1Ia1rOED7Tu6D2p4c4c9OCIkxyPTzSIzp7mvSqoyeKxJdA+y2wHTSf0UMIvEUSDf5p1OiQ3MBAGpnqLW1WlNVsKlB3uC+zOguynKNTBjpqmU6pGimqEviCXaCOYPT5KFrzETaZ/oVYTdcBFTEE2HSVE4Tqke/j1zfpBv+6myqHsMjc92djMOWv7EBw8nAEfqoASLixWhzy1rKrCWljC14E5ZY2LhVmN2eWOjM0iJBBsR2VVPwyHEN2H4ldRLhYgjqWz6t0W42T4xpVGtpim8EvLabHO3oLHOGWm579QAXNEgk8IM6ry7d3ReGxL6T2ubByFrhEES0gjTyVtijg3yavxTsEUsc0YVpo71r8rWlwy1abnNe1pOkw0wDbOAqrw3UBZUaQM7XZ/stsRldLiQGgGPKShcf4ke+ox0hppuL2FoHvl2cuOhJmLmTa5Kr6NV7nktdBPCYtIPLyRTu/BV7xUfJHTY1zg24ADgCfUgn5IeoyDBTiyJnkYSOVyKJ/YHZGvMAOktnUhphzh2mfgVGX37aekqUVXZGtceGHBo5gOPFHYn90O1FhFFxs3ZuYh2aJ/CI+SsKOHqGpuQeCA6oIBBiCAZE+8EDgq2UMg9Fs/Cj2uFYuHE1zGmReMrjObnxZxHYJUJy16XwXntDYEGDdpAEaAWHonHCuWlNVnRJvWdEzs/ky9wzPsjl3sblqM7PupczPuhHZDuGWGEcnDCFaN1RnRB18UByVJYlFWWU7KgYMpfY+ysfax0Se09kj0t+RlsAGC7LlZZ1yb2fyV1mqDHFI6g7qoxW7pDUXf7KOT3WeefxNeTiKNOZinMd3vI/8AULHVgA6G3H1K038SGn2sE6GmzKesEg/ArLtauRnVZGd3pneNB2BquBkTbWNIV1hNoOMZTedOvoqjB0M3otlsXwvvCIPL6suX1GSMOTrwwa48md2rgnPlwbEXP7qnqkvDWNFpgAaucbT58lv9s0xRO6fDhyLSA4TrB5g9D6Qq6r4XytZVYQ5tQZgDFOoOsMLr8oc0mRPRW6fI3GxOWG+lmOq4Yjh/7jHMTb0/Zc+k2dI7ST+qu8ZgsozAyftNdc6e8HfaEz3HNUuMqBpsL91pUm2KeOMFbIsfh4h33tZtft2Wo2f4SfUgue2g3I1/EDUqEFod/lss38zhy0WVoU89RjTbM5oPqQF6Xs/eOoOc9rWPqF+V7nZA4lw4WDTt3iJ6xnk4pe4vpoqc37GP2tRyF27qOcxuRozNaJEQLN00PVD4PDOqtINRsmctMm5gagmwPIDzRO0AQHA8y2fMB39UGykW21a4SII1tBg6aIhJNbk5sLT9JVkpwCmxLOZbEixAgdNEzDsJMRPknXsZ0mnTEZSzGIJ8hKbSlrvVTZOKCcs6+XWOaje0A2v0UpkSje47HDimIDgHD11I7TKhptBN9OZ7Keo8u1k9PLp5J5o5WX+3ceTdPj+yLpAojcY8GCNIgdgLQhwE+m2ZHwRDcJDMx1PJVbosouW6DNnBoZpeTc9LaDkdbq88PY7JVy8ntI9QQ5v/ALD8yz1F0AKQYgteCLEX+YKVF1kUvyRKNwaPQzWPRNNcoaliw5ocNHAH4pd6vRVB8HAbkTnEnok9qcoTVSiojTH2IuQ5+KcqvG41yOfUVZjyk5Yx08DMbdnMxJhHYN06quoq0wTbLlNI3xC1y4OXILlp7Sm+1rz4+JqiYfEVTqux/Ih7nL7MjQeNnh1FuYTL7dRlbLoPkW/HsslS2e6zgBkd7pm15hpPW3yVjt3Fl+Hw4JuW1Kjvz1n0x/40W/FDbGxGZjmE9SB2Otj0N/VcjqcvrcvB2ukThBIsMBRDRcDotpgajd23JOaBI1E9lkcNTGTI7hcAcroMG83vAPw01V54exTKZiqXkC4DWuBeLczIEjNeToubkjHKjsJrT6WN2rs/2mo4tOXJAe0meeUvzRA4o+KpvYDScW5hwusMzXDNOogxNhfsta/Z4xBduaZY2pAfxTcmGh7rC5LTERaeUrNY/Y5puB6OaTH3ZmfKE5QUFSL22tyoxGJklucE3JGptJNwITPD+HbVr56jS8MLWwIDpc6AR5cRkyBAHRGYHCMrYnd0jxVN6KZc5oa4kk02g9SC7XUgAahHeFdtVMCa53Bc4wHQxrqlNzZzTTeLAiRNoPWVohjvnYx5Zbbbmfx9Siaz20mjdAvh771HBocd453I2mBHqUbRxrqtJpeSXsGWzszHNAJsPsPFyRo7XWZrsX4erFzjRovDLHiLSQHOiHchxWhWvhnw3imV3Pq0azYpOLD/AJecvhgDajgWmznG06IyuM1SozYnLHOwBzC45TYkiNfLTWEafDbyIbeBJPM3iwnSf0Rez6zy5/DkAJza5gdIudRz4euiFpbcdvSZ/D14el0iFG/Im2A7R2S9oAyayZIuR25azoq1lEsJm3mteaxqczJBFzyOoHnp5J9bA03N4wWv5mJYbfK8Jia4EyxPkxz3kwHCQdJ1jsVM3ZWYTTM62P7FW52G97iGtBvFoi+gB0M8gp8FhHU7RHyPZS21wU7afJnKNCSO5A+KfXDgC0/XKy1GH8Mmo4ljXOkyABpzi0kqPaHh+oxxNRhZN+IEA2RK+SkNN15MrRpEHpP1+ynrjQI/2bgd+Bw8+KRP+1BVhEdxJ7dv3VbtofGOmLQuMolhEiLAgEjQ3HyQ4cSST9dFFXxBcZKY2pyF1Ki6MrZoNmbaDaeX7vXlNyPKUUPELVlmyLG09e9wmrfiztR0+xgy9OnK/c1f+IGpD4iasoVyb/IYr+OjVf8AH2obE7YBWdSyqSzN7ErAl5NXs/EZlosM2GrM7BpWC1QbFlkfI1ChculcoLHm0rsycyqAoy5PFkmJJyMN44gPMGT/ALh8V2zahbUae4+Bsf1UtS+Gj7tRxHqxgP6KDBjjb3c39Qsk9018m+C2R6Bh8K+pRc1jsubKT+V0i+ojsr/w74caWOGJZUiLPpNc+/UsbDvXVBeH6JzAdf3MBeq4DZ8YczrMfACFwsUp21H5NMqVHl7trswbntYcwcLh/W98rgCCPNZfxN4nZWEPDnkNy/8ALAaxo4Q0NsYPM3Xqe3qVodcd7/qvG/GrmtdlaAMx0AA78vRaOkzyyT0yv+y2S9OqyjoYbe1BM5bEzrHUwtjgsMQGFpJdYiS43zETfXT9FndiD+c0cnNcCfITbrYFbvZWzQ3DCpmzNDy5uosOFzI1kwRHWF0ZtsQ406QTsKo1lA1KkElxphpHFLeJ/FyAzNPfhQ+M2xULs1N2ZsBuThFRobcBo0d5gaEyFFth29cN2CwQAGj7NrkgWMX84ChbsJzgDScKjudMkMq5heWA2qCL2IOtkn8ROjDDFRWtEGFINBwp0yyc2UvcXBxgzJty6LDVg5j5IjWx7fQW+weQv/mkteJgkHNN4FUcxMfiVbivDLnYes50ONN1Mh4dLTJc1wpzGZvUgWLfNMi0kRkxtu1+jODahMciNSrvA44Os59uVp5SqKvh3tGU2AExzMxbzggqGkSDb69EaU+CqnKLpm4pY5tC1N8uJcM33bBpyn7xOa/JsR7zlp/C+xPbHFroJBBc4yXkSBAJ+gvOaFS7RyB+U8+695/hbg2DCh4/zC5wd+UwPkfmVMG5SoXmejG35ZqdlbGp4dgaxosNef8AZN27sSniqLqdRoMgweYPIgqxTK1UNaXEwGgk+QuVsOPZ8v7awO6e5nOwPo4j9vms1W+16ra+La4fUL/vGof/ADc4fqsXVNyslet0da28abAmUp945bdCSewHVdBBtaEUyraDdNySm6jHwCueTqZUmeR3HzHXzUz6YBMX6T/QIV1ipjIo1YoSLjUHcJcqcnYhpoSE+nTkhNhGbPpS5SyDUbCoRHZXoQOyacNVjCWQhhC5OLgkQSeYhKiG7Kqn7BUo2JW+7CbqRWiXEYQspUp/5rDVH/SalSm0+opk+oQmxqObEUm9ajR8DdGbba5hph0jgaA06hrRlaD8FZeFK9JrHPLQKjTBdqQ03kdNCLdFhzT0wckjdjXhm+2dRLa1JsdH5uXBxPH/AGlev1arWkM5kEjyED+i8h2BUr4l7DScGEMc6XNzsEOhuZoveYsdOXNP2l41xtLEODmiq1joa0EOgOIgWDajhpBLTrfquXgfbi/djZx1NGk8V1RDl4d4hwlStXljZaLTmYBM394hbXa3jYVnNp1KT6JeQ0uOYhoJguLS0OIHQLK7OwYrOJ1c17mzyLRdst6kEJvRY2pynJfA3TqqI7Z+znsgltIBpuXuD7jUZG66f3V/tXGtY0QZawW4cjRN+Ck0nLbu5x5nkKPaOyntOak0PgSWnOH2/MA6egv2KZhMQK4ltQCo0f5byWvJaLinAyuIjSQey2uL8GmOiMqfP5LTZG2WVAN0ZqGTlNiRyy9bCevwCPfUdBcC5urTlkG4u3NI1WbxWzqdQSRu6n+pTEXH+pTMBx7iD1JVhszaFWnUp0cU7e0NKdZpdALjLW1M0ESeHjEidSFCjF7xZdZZw2yr9oKr7akjNSzuJDTVqvc57ZIAcyIaz1Dha8ixsaeKYZ3tQPeQAXMz0zVAsWVGPJAmxGVwbeMogKur0zmc0Wmflcj5Qod0xkF7sxMcAkyOhcNPSVNSnt4JnGMPUmT4/Y9GsCKVnyTuqpyOAjRo5g9zyGqytXCFpLSACDltEWJm497zlbt9bDmmwOaWkG27Jc+lzDm1JsZ+yZnpN1U7SpZ31JdnqsGZzspG8bE5iB7rxbNJjnyKs41sLTT3KTC0RlBvmB0i0Eag+YPxC9Y/hr4np0opVDl3h4SYDQ8AcJP2ZEeoHVeXYBhfMNLovbQBWNEEHSCD1kT3KIJxepCsijOLg2fSPtjI94epA+SwXjzxtT3bqNJ//W4X/LqPoLz+htipxAvdkAfYuOWzCLXjmDAVHiK2YxPn0CbLNWyRnx9IuZO0T7afTq0aRbwOaHB8g8fHIe2JAImCDGk3WRfckd1f1WTTc7kIHpfp9XVrsPwsNy7fcO9DYsCacSWvPPndvMTziE71Y7JSVGEcIRWBZnMc07a2AfRqOpvEOb6g2kEHmCIIPdV4xJaOEwSNeforL1LYyNbhO0SGOLRBI1jQdlWuU7KUzf8AukdSICZGlsToBlPh3TZMbSn+6YHEGRqEyxMl4DtyehVlsjDGbhafYuGZiKDagAnRw6OGoRJwjW6AKvcV0IaZJhacNHkp8yE3q7fKSpHWxPEUqFftBk31XIoC9DB0CrttVS3dZSW5nw6CRIy6GNQuXIXJaPKMDtKqXPlxLjxXJJPvu6ozYZvU/J/uK5ckZvtv/vJtgev+A7U6sfj/ANyzPiY//qZ9faSrlxnyvhjo8v8AQ7E1SXMBJIztsSY16LIYMw2tHJ1Ijseo7rly3/8An/bfyTP6v0arGiaRPUMnvYm/qB8FiduWdSI1LHEnmSHOgk84XLls/wA2aM/2kXNSs5woucS5zqNMucSSSSLkk3J7oyjeAdCYI5EToUi5ZH9f7NsPtI0e3MO1rSQ1oJpgkgAEneuEk9YssqNXeS5cugzlLwWtdsZALDKLctFVbYqEYh8EiXkGDEi9j2XLliw/Q/k1PwaHw0wexssL1RPfU3Vhtcfyx6Lly34uDLk5KvaVQjBMgke+bHmHEA+ap6bB7DUMX3lETzgtqSJSLkrP9f6LYPofyFbFpgsuAfdNxN95TE/An4q8Lz1XLkT4j8GXL5M1/EJo3WHdF8tUTzgOECegk/FYSlquXJeLh/LJ9vhf6Cqakriy5cp8m2H0srnphXLk5HPnybDwI85Kokxmb+iumu4yuXJL+4Z5EzQm1PdPkuXJosxWLPG7zSLlysSf/9k="><img 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" alt="" border="0" /></a><span style="font-style: italic;"><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />(Robert Downey Jr. plays Tony Stark, defense contractor, billionaire playboy, scientific genius, and alter ego </span><span style="font-style: italic;">Iron Man</span><span style="font-style: italic;">. Image from www.comicbookmovie.com, still from Iron Man 2)</span><br /><br />On Tuesday, May 3, I sat in on part of the Market Focus talks at the CLEO expo on defense. The Market Focus sessions cover various business and commercial applications of optics research. Last year was the first time I attended a Market Focus session, and I knew I had to go back. It is a little expo in itself that requires no walking- you to sit down and find out trends and problems that need solving in particular commercial areas. Great fodder for new research ideas!<br /><br />Although the sessions are broken up into specific talks, what makes these sessions unique is that they turn into a round-table discussion at the end (and even during) the session. They have a more intimate and informal feel than the technical talks and have been organized with a specific agenda of bringing the attendee to a common understanding of the particular market being addressed.<br /><br />For example, in the defense session, moderator John Koroshetz from Northrop Gruman Laser Systems laid out the logical order of talks to help us get our foot in the door of defense contracting: 1) Science and Technology Development, 2) Product Development, 3) Manufacturing, and 4) The Soldier's perspective. The aim was to help a novice understand the cycle of product development, funding, testing, manufacturing, and end-use, which often cycles back to development for upgrading and enhancing the product into its next-generation phase.<br /><br />The first speaker, Craig Hoffman, from the Naval Research Laboratory, described science and technology development of infrared imaging systems. He broke up NRLs work in this area by spectral region:<br /><br /><span style="font-weight: bold;">-Visible:</span> 0.4-0.7 microns (high photon energy makes devices tolerant to noise, but scattering makes it bad for imaging through dust or fog)<br /><br /><span style="font-weight: bold;">-Near IR:</span> 0.7-3.0 microns (better for imaging through climate, but resolution gets worse because the wavelength is getting longer; becoming less tolerant to noise)<br /><br /><span style="font-weight: bold;">-Mid-IR:</span> 3.0-5.0 microns (getting very good at seeing through climate, but getting even worse with resolution and noise tolerance; detectors may need to be cryogenically cooled to circumvent thermal noise)<br /><br /><span style="font-weight: bold;">-Longwave:</span> 5.0-14.0 microns (least prone to scattering, worst for resolution and noise)<br /><br />NRL is looking to piggy back imaging systems in these regions for applications in target acquisition, surveillance, and reconnaissance. The shorter wavelength systems use reflected light to gain information about detail of a target whereas the longer wavelength systems make use of emissive properties of a target to gain bulk properties like thermal imaging.<br /><br />For example, new thermal imaging systems use mid-infrared light detection to gain detailed information about a target, but also use longwave detection in order to gain a wider field of view. You need both since by themselves the former sacrifices field for resolution and the latter sacrifices resolution for field.<br /><br />Hoffman went on to describe military imaging problems that need better answers 1) Detailed target identification. You don't want to just know if a target is a tractor or a tank, but exactly whose tank it is (friend or foe?) and with enough time to either make evasive maneuvers or decide how to engage. 2) Fast data acquisition for reconnaissance. For this application, you want to collect data from an aircraft that is flying high and fast. You don't have the burden of real-time analysis like target acquisition (you can spend weeks later to analyze data), but you do need to collect enough information, with enough quality during the short acquisition time. 3) Surveilling a small area for weeks on end to look at changes in patterns like traffic flow, building construction, etc.<br /><br />Hoffman spoke briefly about things like SWaP- size, weight, and power. This acronym represents all the things that should be as small as possible for a viable military product. Pete Vallianos from N2 Imaging systems followed up Hoffman's talk with more of the parameters, tests, and requirements related to SWaP. Vallianos underscored the importance of practicality and robust requirements when it comes to making products for the military. He repeatedly reminded the attendees that the military is not interested in your research per se (definitely not technology for its own sake), but rather interested in how technology might<span style="font-style: italic;"> solve problems</span>. While being developed, it needs to go through a variety of rigorous tests- one of the stress tests from the Marines is dropping your product from a height of six feet onto a piece of plywood . If it doesn't survive, it's back to the drawing board.<br /><br />Vallianos described some specific product development interests of the military in imaging:<br /><br />-microbolometers<br />-small eye safe lasers<br />-CMOS, low level light detection<br />-lightweight visible optics<br />-high transmission in optics across the visible spectrum through the longwave IR<br />-moldable aspheric lenses<br />-robust broadband optical coatings<br />-OLEDs<br />-LCDs<br />-Lightweight optical "network" on a soldiers back<br />-Any decrease in power for powered optics to get grid of as many of the batteries as possible a soldier needs to carry in his or her pack.<br /><br />Though the speakers did not describe any iron suits with flying capability, or magic cold-fusion-like power supplies, I think Tony Stark still would have been proud of this session.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com1tag:blogger.com,1999:blog-8860229920122250605.post-81255151630698577262011-05-05T14:29:00.000-07:002011-05-05T14:56:02.235-07:00Post-deadline PrepJust wanted to chime in with a nagging note to remind you to plan your post-deadline itinerary before 8 pm. I am going to commit to <span style="font-weight: bold;">PDPA-Session I</span> and not try to hop around the standing-room only crowd. I am particularly interested in the supercontinuum generation and frequency-comb work in this session, some of which is pushing into the mid-ir where there are interesting chemicals to identify for spectroscopy and stand-off detection. Other broadband generation in this session has been performed with small waveguides or micro-resonantors- little pocket combs on silicon (<a href="http://cleoqels2010.blogspot.com/2011/04/postdealine-papers-show-emphasis-in.html">see the April 20, post for more details)</a>. I will be disappointed to miss the new Applications and Technology Session, particularly the biomedical work. These groups by far always have the coolest pictures, images, and videos. If you can make it to these talks, the first four of <span style="font-weight: bold;">PDPB-Session II</span>, be prepared to be blown away by beautiful videos and images that address improving image acquisition rate, penetration depth, and resolution <a href="http://cleoqels2010.blogspot.com/2011/04/postdealine-papers-show-emphasis-in.html">(again, see the April 20, post for more details</a>). Very likely, these state-of-the-art techniques may be used on <span style="font-style: italic;">you</span> in your lifetime. You can tell your doctor, "I saw this work at CLEO 2011 before you even graduated from med school."Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-25533753125432353112011-05-04T20:51:00.000-07:002011-05-05T00:14:07.310-07:00The Romance of Photonic Lattices and Ham<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9NcHAWgoE3lSc8zSzSZUiVc6HI-l1wxm2SWIHxoxu6Ov7KloUgzcyHvaRewktj5WVvdunZNjDa-Dhvm9dbdvtQWeTj0da8VXNKz1P-mpKQheYrxs-BcOc9sV7PwTtVN8Hey3Nq7VcyZU/s1600/localization.png"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 139px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9NcHAWgoE3lSc8zSzSZUiVc6HI-l1wxm2SWIHxoxu6Ov7KloUgzcyHvaRewktj5WVvdunZNjDa-Dhvm9dbdvtQWeTj0da8VXNKz1P-mpKQheYrxs-BcOc9sV7PwTtVN8Hey3Nq7VcyZU/s400/localization.png" alt="" id="BLOGGER_PHOTO_ID_5603094442278137682" border="0" /></a><span style="font-style: italic;">(Left: beam profile in one of </span>Mordechai <span style="font-style: italic;">Segev's 2D photonic crystal lattices. The transverse disorder increases from c) to e). From </span><a style="font-style: italic;" href="http://www.nature.com/nature/journal/v446/n7131/full/nature05623.html">Schwartz, Segev et al</a><span style="font-style: italic;">)</span><br /><br />This year's CLEO plenary sessions were exceptional. Monday evening hosted talks by Donald Keck, who pioneered the first <a href="http://cleoqels2010.blogspot.com/2010/12/how-my-mother-in-law-and-rural-us.html">low-loss optical fiber</a> and James Fujimoto, renown for developing<a href="http://cleoqels2010.blogspot.com/2010/10/your-mother-may-think-youre-special-but.html"> optical coherence tomography</a>. Wednesday morning's plenary followed with exhilarating work (I'm serious, not just blogger hyperbole here) on photonic crystals. Even the awards were exciting. Amnon Yariv, responsible for the creation of the distributed feedback laser, and whose book "Optical Electronics in Modern Communication," I safeguard as one of the most helpful optics texts on my shelf, was presented with the 2011 IEEE Photonics Award. In his acceptance speech, he spoke briefly of his emigration to the United States from Israel 60 years ago. The freighter that carried him, other passengers, and iron ore across the Atlantic, made entry in none other than the city of Baltimore. Yariv, reminisced about his first meal after landing in a gritty, industrial, 1950s Baltimore-a ham sandwich (his first ever)!<br /><br />After the awards, the plenary speakers Mordechai (Moti) Segev and Susumu Noda spoke about their respective work on photonic crystals. Segev, a charismatic speaker, setup a beautiful story addressing a fundamental understanding of periodic and random structures via photonic lattices. He specifically spoke about work on Anderson Localization of Photons, the optical analog to Anderson's Theory for Localization of electron's in a crystal lattice. By introducing disorder into a 2D photonic lattice, Segev was able to constructively interfere light over a small area, and destructively interfere light everywhere else. Diffraction is thwarted, analogous to how diffusion is thwarted by the interference of electron waves for Anderson Localization in a crystal lattice (see figure above). Check out <a href="http://paramountistcleo2011.blogspot.com/2011/02/small-structures-huge-effects-what.html">Frank Kuo's February 26, blogpost </a>with more details describing this work.<br /><br />Segev's group of course has pushed this work further, and into stranger directions. In contrast to confinement, Segev's group found that they could make a beam expand faster than diffraction, hyper-transport. One reason this work is so beautiful is that the theory and phenomena for photonic lattices can be borrowed from crystal lattices in condensed matter and visa-versa. The equations are the same, you just need to change the variables and some good creativity. In 2008, <a href="http://www.nature.com/nature/journal/v453/n7197/full/nature07071.html">Roati <span style="font-style: italic;">et al</span></a> leveraged work from Anderson Localization in photonic lattices to demonstrate Anderson Localization for the first time using matter waves. This makes me wonder about a designing a crystal structure with say hyper-diffusion? With a sharp mind and good imagination, the possibilities seem endless.<br /><br />Segev does a fantastic job framing his work romantically. Though the devices his group makes have great practical implications, it is all through the guise of exploring the nature of world. Segev helps remind us why we became interested in science in the first place, for the thrill of exploration and finding answers, to generate new questions, and to pursue things because they are beautiful.<br /><br />Segev was a tough act to follow, but Noda came through. After Segev's nice setup, Noda showed one impressive photonic crystal device after the other. Here is a list of some of the groundbreaking devices he has made:<br /><br />-Nano-cavities with Q > 40,000<br />-Inhibition of spontaneous emission<br />-Light that can make right angle turns<br />-Slowing or stopping light with probe pulses<br />-Novel gates for quantum computing<br />-Small beam-steering devices<br />-High-efficiency, high power single wavelength emitters<br />-Creation of unique beam patterns for applications like optical trapping of non-dielectric particles<br />-Sub-wavelength focusing of beams<br />-Thermal emission control (shaping and redistribution of blackbody spectra)<br /><br />Again, for details on the physics behind some of these devices, <a href="http://paramountistcleo2011.blogspot.com/2011/02/small-structures-huge-effects-what.html">see Frank Kuo's February 26, blogpost</a>. I left this plenary session inspired, ready to get into the lab to get some work done, and strangely with the craving for a Baltimore ham sandwich.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com0tag:blogger.com,1999:blog-8860229920122250605.post-9559939212832653372011-05-03T13:01:00.000-07:002011-05-03T14:59:08.248-07:00Lasers can Mold and Manipulate Metal as easy as Play-doh<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXnO830VADJ7nqvMCrNmD1Zo_oDJ7cZZtvb7tkM_-ylBAb9ULIWwx7hkmLlOEFu1jS6ZsNk19SW_KMTWZbHgbWxont5I9pNgQsBJxsngWc6ylpdHMUi4Mm4Fhf9ZEk_40WrezIKLwWH7E/s1600/marshall2.jpg"><img style="float: left; margin: 0pt 10px 10px 0pt; cursor: pointer; width: 286px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXnO830VADJ7nqvMCrNmD1Zo_oDJ7cZZtvb7tkM_-ylBAb9ULIWwx7hkmLlOEFu1jS6ZsNk19SW_KMTWZbHgbWxont5I9pNgQsBJxsngWc6ylpdHMUi4Mm4Fhf9ZEk_40WrezIKLwWH7E/s320/marshall2.jpg" alt="" id="BLOGGER_PHOTO_ID_5602608029329372786" border="0" /></a><span style="font-style: italic;">(Left: Dr. Marshall Jones from GE Global Research; </span><a style="font-style: italic;" href="http://ge.geglobalresearch.com/blog/happy-golden-50th-anniversary-to-the-laser/marshall2/">Photo from GE</a><span style="font-style: italic;">)</span><br /><br />The head of the student machine shop at Cornell, Bob Snedeker ( Sned), liked to remind us in a sarcastic fashion that its easier to take material away from a workpiece than to put it back on- warning: be careful about how much you take off as you cut. Or as the old saying goes in carpentry, "measure twice, cut once." This is not necessarily true for laser machining of metals. Laser cladding, which was one of the topics discussed in the tutorial, AMB1 "Industrial Applications of Laser Materials Processing," by Dr. Marshall Jones from GE Global Research, is a technique in which material can be added to a workpiece where too much was accidentally cut off. Like Play-doh, you can just put back on what you need. Wow, if only I could have laser-cladded my tool bits, and special nut and bolt we were required to make in order to graduate from machine-shop training! Sned had high standards and we spent many hours to make a piece to find out we needed to start over with fresh stock. It was back to the grindstone (literally!) until those bits had a perfect angle and facet.<br /><br />GE uses laser cladding to clean up mistakes that may have been made for particularly expensive pieces such as airfoils for aviation. You don't want to throw these out and start over. Laser cladding is also used for coat metals with another protective metal surface- hardfacing.<br /><br />Another laser processing technique explained by Marshall was laser-shock peening. Peening (as in a ball peen hammer-a remnant tool from days of blacksmithing) is a technique that reduces the fatigue of a metal (like preventing cracks from spreading) by applying a compression force to the surface. In the old days, this was done with a hammer, Marshall uses a "laser hammer." To create a shock wave powerful enough to peen, you need a laser beam with an a power density of 10<sup>10</sup> W/cm<sup>2</sup> and an interaction time with the surface of no more than 10 ns. Using an interface like water, through which the compression force propagates to reach the metal surface, can make peening more effective. GE also uses shock peening for aviation pieces in order to extend the life of a particular part.<br /><br />Marshall also discussed a handful of additional applications for laser welding at GE. GE rail uses laser welding for their diesel engine heads and liners. Their consumer division uses it to weld electrodes of ceramic metal halide lamps- the ones that give a nice <a href="http://cleoqels2010.blogspot.com/2011/03/cleo-technology-sparks-controversy.html">white-light spectrum</a> crucial for lighting for retail. Marshall brought up the fact that jewelers and clothing retailers particularly need white-light illumination in their stores to ensure customer satisfaction (you don't want what you thought was a red dress to turn out to really be magenta when you leave a shop and get out into the sunlight). The ceramic metal hallide lamp electrodes are particularly tricky to weld together because of the need to join odd materials W:Mo welds and Mo:Nb welds. GE uses a special three-beam laser system to join these materials.<br /><br />Finally, Marshall briefly discussed the laser systems themselves used for such applications. The conventional lasers used for processing are CO2 lasers and Nd:YAG systems that give out approximately 20 kW average power. Unfortunately they have 10% and 3% wall-power efficiency respectively, and CO2 lasers require expensive specialty fiber for coupling due to the long emission wavelength. Ytterbium-doped fiber lasers and ampliers are beginning to replace these current workhorses due to high wall-power efficiency, 30%, and all-fiber configurations (zero optical alignment and high flexibility in footprint and beam delivery). The main disadvantage to high-power fiber lasers is expense. However, as fiber-systems continue to be developed, they may very well replace their bulk system competitors in the near-future.Jimhttp://www.blogger.com/profile/06319896682438398594noreply@blogger.com2