This post originally appeared on Jim’s CLEO Blog and is reproduced with permission from the author.
Flying 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 Cafe Frascati still in my system. However, I feel like something big is going to happen, particularly in the field of photonic circuits and nanophotonics.
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 On Demand video 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.
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.
Yurii Vlasov used imagery from the Wizard of Oz 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.
From Postdeadline paper CTh5D.1 "Wavelength-Size Silicon Modulator." Scanning electron micrograph of the silicon integrated waveguide modulator.
This article was originally posted on Jim’s CLEO blog and reproduced with permission from the author.
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:
CTh5D.1, “Wavelength-size Silicon Modulator” from V.J. Sorger et al.
This is work out of the Zhang Lab 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 CW1k.1, “Single-chip Integrated Transmitters and Receivers” 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.
CTh5C.4, “In Vivo Three-Photon Microscopy of Subcoritical Structures wihtin an Intact Mouse Brain” from N. Horton et al.
This work from the Xu Group 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/z4 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?
CTh5C.1, “Demonstration of a Bright 50 Hz Repetition Rate Table-Top Soft X-Ray Laser Driven by a Diode-Pumped Laser” from B. Reagan et al.
This work from the Rocca Group of Colorado State University and the Research Center for Extreme Ultraviolet Science and Technology 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 March 2012 Laser Focus World 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.
ATh5A.4 “Highly Efficient GaAs Solar Cells with Dual Layer of Quantum Dots and a Flexible PDMS Film” from C. Lin et al.
In this paper a Taiwanese collobaration from the Institute of Photonic Systems, 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.
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.
This post originally appeared on Jim’s CLEO blog and is reproduced with permission from the author.
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?
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.
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.
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 not the threat. You can’t and don’t want to blatantly 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.
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/r2 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 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…
(To find out some of the specific lasers needed for current standoff-detection projects, more system requirements, and to read the entire post, click here)
This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.
I am pretty sure you have loaded up your crazy mind with a big chunk of knowledge on Wednesday. Plenary session, a whole day of exhibition, and enthusiastic poster session guarantee everyone finding its own corner. What excites me the most is to see the interplay between different research fields. Like all of us today, I am happy to learn that photonics also finds its applications at each corner of the science. Let’s encapsulate a couple of them:
! Harvesting green energy with the help of photonics fibers !
Converting the solar energy into chemical energy is not a new idea. One interesting way of doing so is to grow algae, such as cyanobacteria. After you grow tons of them, you essentially squeeze them to get Algae oil, which is used to fuel the world (I sincerely hope it smells like olive oil). However, just like everything in the practical world, it faces some challenges, especially in terms of efficiency. It turns out that cyanobacteria are very picky about where they live. The amount of sunlight has to be just right for them to prosper. Like figure 1 shows, the optimal condition is only about 10 cm thick somewhere below the surface of the pond (or pond reactor). Same situation applies for the tube reactor. As you can see from the figure, most of the space is wasted.
Figure 1. The optimal zone where the algae grown. Courtesy of D. Erickson at http://www.cctec.cornell.edu/events/ctvf11/Jung.pdf.
Above: A morning performance in the Lobby before the CLEO morning session.
Networking Games:
If you haven’t done so already, stop by the OSA booth or IEEE booth in the registration area and pick up your game piece for CLEO:Expo TechPlayground. This was a brilliant idea from the CLEO conference management and the Exhibit Committee.
First, play the game and you have a chance of winning an iPad 3. There has already been one drawing and there are two to go. Tomorrow will be the last day to play. In order to get your name entered in the drawing, you have to get your game board stamped by various companies at the Expo.
What makes this game and idea so fantastic is that it is an easy icebreaker for the wary student. I remember when I was in grad school having no idea how to go up to conference presenters or reps from companies. On the other side of the coin, this game encourages those who are bold enough to branch out. As I went around to various companies, I felt compelled to find out something about them and try to see if my research could fit with their products. It seemed wrong to just go and get the stamp. What I found was that a handful of the companies on the game board did have some connections with my research, companies I never would have visited were it not for this silly game.
Additionally, Newport, one of the companies on the list has a game of their own. Using a mirror mount, you need to steer a beam to hit the duck, bottle, and random objects a-la-carnival style. If you hit enough items fast enough, and in the right order, your name gets entered into a drawing for an ipod touch.
Video Content:
You may have noticed in your conference planner that there is the “play button” icon on various talks. These talks have been recorded and uploaded for “on demand” viewing. This was extremely relieving for me when I realized that I could view many of the talks I had missed because of conflicts. For me this was particularly true of the 50th Anniversary of the Semiconductor Laser Symposium. Because it is out of field for me, I chose to go to other sessions. At first this was a tough decision because of the line-up of such heavy hitters in the symposium. Once I found out about the video content, I relaxed. This entire symposium has been recorded and uploaded. I then changed my itinerary for later days to cast a wider net for viewing talks. Some I will see in person, some back in the hotel room, and some later at home.
Finally, keep an eye out for those kooky Team San Jose folk- the ones responsible for handing out stress reliever hard hats and getting Million Dollar Quartet to play in the lobby for some the impromptu Elvis Rock this morning. I’m waiting for a guerrilla break-dancing team to spontaneously perform a routine during a tutorial. Thanks for keeping it fun Team San Jose!
Wavelength Modulation Spectrum using tunable 2.0 micron VCSEL; From JTh1L.6, A. Kahn et al,. "Open-Path Green House Gas Sensor for UAV Applications"
This post originally appeared on Jim’s Cleo Blog and is reproduced with permission of the author.
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 CM1B, Ultrafast Mid-IR in which 5 out of 8 papers demonstrated ultrafast pulses about 2.0 microns. Today there was a session titled CTu2D,1.5 to 5 micron Lasers 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:
-CM2B.2, “A Broadband 1850-nm 40-Gb/s Receiver Based on Four-Wave Mixing in Silicon Waveguides”
-CTu3M.7, “All-fiber 10-GHz Picosecond Pulse Generation at 1.9 microns without Mode-locking”
-JTh1L.6, “Open-Path Green House Gas Sensor for UAV Applications”
-CF1K.1, “Single-Frequency kHz-Linewidth 2-μm GaSb-Based Semiconductor Disk Lasers With Multiple-Watt Output Power”
-CF1N.4, “Double-wall carbon nanotube Q-switched and Mode-locked Two-micron Fiber Lasers”
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 year’s conference, but 2.0 micron products at the expo as well.
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, Mark Arnold, 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.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.
Many of the companies I spoke with selling 2.0 micron components and sources confirmed such spectroscopic applications of their customers:
-Oz Optics now sells passive fiber components at 2.0 microns as well as DFB sources.
-Sacher Lasertchnik and Nanoplus make DFB lasers extending through the 2.0 micron region depending on your molecule of interest.
-Advalue Photonics makes thulium-based fiber laser systems and sells passive 2.0 micron products.
-New Focus will be developing tunable laser diodes about 2.0 microns in the next few months.
-Nufern and CorActive are selling Tm- and Ho-doped fiber for 2.0 micron amplification and for fiber sources.
-IPG 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.
There are other advantages to 2.0 micron light as well… (for a list of more companies and the rest of the post, click here)
This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.
If you attend “QM1H • Spasers and Nanoemitters” today, you know exactly what I am talking about. Exciting new materials, including metamaterials, quantum wells, and quantum rods, are used for the realizations of the nanolasers. If you missed it (which is quite possible since there are many other outstanding technical sessions packed today), this short article is your second chance. Three examples of nanolasers are presented here (summarized from today’s speakers) to give you a taste of the flavors.
Nanoscale coaxial lasers:
This is a piece of artwork of nanofabrication. The researchers from UCSD are able to fabricate a nanoscale coaxial laser cavity on an InP substrate (figure 1). It is composed of a metallic rod with different coaxial disks. One of the disks, the gain medium shown in red, is made of 6 quantum wells (each one is made of Inx=0.734Ga1–xAsy=0.57P1–y/ Inx=0.56Ga1–xAsy=0.938P1–y, with an overall height of 200 nm). They are sandwiched between SiO2 and air plugs. With the help of these two plugs, the entire device behaves like a cavity which supports a few sparse EM like modes (figure 2). If you pump the device in a right way, you can excite these modes and build them up. The lower air plug also allows pump energy into the cavity and couples out the light generated in the coaxial resonator. So once you build up the modes, you can couple the light out. In other words, you can make this device lase.
The researchers pump this nanolaser with a 1064 nm laser and it will lase at 1.26 and 1.59 micron at room temperature depending on the overall structures of the nanodevice. I would like to have one of these as souvenir.
Figure 1. The structure of a coaxial laser cavity. The enitre thing is ~ 500 nm in all dimensions. (b) and (c) shows the SEM images of two different structures. Courtesy of M. Khajavikhan et al. in Nature 482 204 (2012).
Figure 2. The EM like plasmonic modes that can be supported by the cavity. Two different structures support different modes. Some of the modes can be pump and excited by 1064 nm laser. Courtesy of M. Khajavikhan et al. in Nature 482 204 (2012).
The weather is going to be gorgeous this week in San Jose. So, if you have the opportunity to get out in between technical sessions or in the evening, be sure to take adavantage of some of the great area attractions and restaurants. The city of San Jose is so excited to have you visiting, they have arranged several Show Your Badge discounts specifically for CLEO attendees. Here are just a few of the venues you can visit and receive discounts up to 40%:
-Children’s Discovery Museum of San Jose
-San Jose Museum of Art
-Tech Musuem
-Loft Bar & Bistro
-Sonoma Chicken Coop
-Broadway San Jose
San Jose also has a Discover San Jose discount card that you can pick up at IEEE Photonics Society, APS and OSA booths and receive even more discounts at area restaurants and services.
This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.
There are many things you do not want to miss in CLEO: 2012– A conference full of high quality technical sessions spiced by cutting edge presentations from invited speakers, not to mention the inspirational talks of renowned plenary speakers. For young graduate students, these are stimuli they want to boost their research. On the other hand, in the mind of senior graduate students, there is one more mission besides getting loaded with technical knowledge – Landing on a job after graduation. The good news is that you can get two birds with one stone since CLEO provides a nice channel for you to get connected with your potential future employers.
If you are interested in staying in the academia, your advisor(s) and the department may be the best resources for you. However, if you consider changing the tracks and exploring the industrial career, CLEO: 2012 is something you cannot miss. It brings employers from the entire US under one roof, and you get to meet them all. This year, you can try the online job fair by CLEO and WORKinOPTICS by OSA to get a head start. Unfortunately, not all the employers are actively involved in the online job fair. As a result, walking throughout the exhibition hall will be your next move.
Trying to get exposed in the exhibition hall is a must. To get you exposed in a right way is not that straightforward. For the past few years, I feel lucky to have the opportunity to look into these job-hunting games from both sides (as a senior graduate student trying to impress future employers in the conference, and a employee actively working in the tradeshow). Here are some tips I hope that help:
(One of seventeen youtube shorts from the program chairs highlighting hot topics for CLEO 2012)
This post originally appeared on Jim’s CLEO Blog and is reproduced with permission from the author.
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.
Conference Program Stats
-The 2012 program has been selected from a record number of submissions.
-In just its second year, CLEO’s new Technology and Applications Conference saw a 50 % increase in submissions.
-350 papers, 15 % of all submissions, live in the subcommittee sections “Nano-optics and Plasmonics” or “Micro- and Nano-Photonic Devices”
-Subcommittee section: “Fiber Amplifiers, Lasers and Devices” was the single committee that received the most submissions
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.
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
The Advanced Light Source (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.
On the other hand, Mielke will be discussing the use of compact fiber systems for micromachining and laser surgery. See blog post “Machining with Ultrafast Pulses” for some stunning videos and more information on these compact micromachining systems.
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.
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.
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 2010 Nobel Prize 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.
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. CLEO Applications and Technology: Energy and Environment
In his video short, subcommittee chair Christian Wetzel from Rensselaer Polytechnich Institute discusses two trends… click here to read the full original post
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