http://www.woodlibrarymuseum.org/Finding_Aid/kornfield/mac-online-casinos.html best mac casino www.woodlibrarymuseum.org new online slot machines secure online casino games at the best casinos play online blackjack for cash blackjack casinos for real money 2013 online casinos for usa players new usa casinos us online gambling deposits online casino deposit methods best online slot machines for money best online slot machines for money online gambling with us credit cards casinos accepting credit cards easiest payout casino online quick withdrawal online casinos united states roulette gambling online roulette for usa players casino gambling most popular casinos online http://asb.cgiar.org/Gen2/about_us/online-casino-slots.html online casino slot machines learn more here sign up bonus for blackjack play online slots games play online slots mastercard online casino for us players mastercard casinos

May 21
There is no break in the review conference. Everyone is eager to share with others about their ideas. People were shuffling around to maximize the precious time together.

There is no break in the review conference. Everyone is eager to share their ideas. People were shuffling around to maximize their precious time together.

By Frank Kuo – Paramountist Blog



Being an active OSA young professional comes with additional bonuses once in a while. This time, I was happily summoned as “scientific paparazzi” to sneak into one of the committee meetings for CLEO: 2013 happening in the DC metropolitan area. Digging for insider info on CLEO’s hot topics and from CLEO: 2013 committee chairs and members –  as they reviewed, scored and sessioned all the CLEO papers was the top mission.

My first impression about this conference is the vibrant energy. All the chairs and committee members were holding such high spirits. I don’t feel they came to the conference as referees to select the best papers. I feel they came to learn more and look for new inspiration.  While it can be difficult to make decisions on which papers represent the best in the field – they are there to do their job – accepting only the highest-quality papers for the CLEO: 2013 program.

My first personal encounter  with one of the Chairs was a short conversation with professor James C. Wyant,  who also served as President of OSA in 2010. As program co-chair of “CLEO: Applications & Technology,” he is very happy to see CLEO is creating a trend of applying its strength in core science into applications. This, of course, will foster more interaction between academia and industry. He is especially keen on the topics about “metrology” and “sustainable energy – laser-driven inertial fusion energy”. If you are still not aware of these two topics, I strongly advise you to check out the short course on metrology, and the tour of the National Ignition Facility (NIF) to learn more and gain a first hand experience. All of these sound very exciting.  Joining the tour allows you to have the chance to see one of the most powerful lasers in the world, and how to use it to mimic the core of the sun.  And, the metrology course will introduce you to the tabletop X-ray light source that is one of the prominent rising stars in optical science. You better grab your opportunity to attend by checking out the CLEO website now.

Professor Wyant also shared the concern about the impact of U.S. federal government’s sequester on optical science too. Although we all feel sorry about the cuts on  financial support, he is cautiously optimistic. Optical science has found its applications in many aspects of our society, and many more will come. With all of  humanity benefiting from optical science applications, we shall look for more that originate from optical science to accompany our future. Thanks to him and many other researchers, we are striving toward this goal.

Then, I was lucky to catch a few humorous and witty scientists during the lunch break. Having a meal together with Professor Christian Wetzel, Professor Mark A. Zondlo, and Dr. Max Shatalov – manager of SETi. They all serve in the session of environment/energy.  They were impressed by an increase of the number of the submitted papers. To me, it seems to make sense. With the population of Homo sapiens increasing, the Earth is barely breathing. Without our effort, we will definitely engage into an irreversible future. As a result, taking care of the environment must become our priority, and I am happy to see research that is helping to make this possible.

They also told me about some interesting topics you should not miss:

1.      Using the quantum cascade lasers for the environmental sensing: We are all very excited that QC lasers are finally portable and can be brought to the field for various applications. For example, trace gases like SO2, methane, or air pollutants are all targets under the scrutiny of QC lasers. If you are a green-oriented person, you should not miss this opportunity when you come to CLEO: 2013. In addition, we were discussing a very interesting paper in which a laser is used to probe the “particle size.” Again, if you feel intrigued about it, you just have to keep your eyes open for topics like these while wandering around in the conference center.

2.      Using UV-LED, for sterilization and water purification: This is a perfect example of how optical science is helping the humanity. UV-LED, being more compact and consuming less energy compared with traditional light sources, will probably become the main light source for food sterilization (in our discussion, UV-LED shining on strawberries was the content). The environmental impact of adopting this new light source into the food processing chain is self-evident. Cool science with a mix of practical goals – I guess this is yet another reason  why CLEO is awesome.

3.      Solar energy harvesting: How to harvest solar energy in a more efficient way is always an attractive scientific challenge for the researchers. In our short break, we touched on the topic of multi-junction cells, patterned surface — either nano or micro scales to trap more light into the solar cells, and using organic media to harvest the solar energy. Checking out the talk presented by Rebecca Jones-Albertus is a good entry point for you to delve into this domain.

In order to please the crowds of hard-core scientists, I also had a short chat with professor Zhigang Chen, who is serving for the CLEO: QELS Fundamental Science session of Nonlinear Optics and Novel Phenomena. He mentioned with zeal to me the breakthrough in plasmonic resonance, arbitrary trajectory manipulation of light propagation, using photonic periodic structure to test the idea of super-symmetry, and so on. The depth of the fundamental science he was trying to convey blows me away. Topics like these will always find their places in CLEO, and I always feel this is one of CLEO’s strengths. In fact, the entire QELS program poses a mental stimulus to my brain.  These courses are  so stimulating they are like “ “espresso for the brain!”

The truth is  what I mention here provides  just a small glimpse into all the great content being featured at CLEO. To get a glimpse at the full conference program, visit the CLEO website here!

View exclusive interviews with the Chairs and get more personal insight on hot topics and trends at CLEO: 2013.


Apr 30
Iain McKinnie, Lockheed Martin Advanced Technology Center,  CLEO: Applications & Technology 2013 Program Chair

Iain McKinnie, Lockheed Martin Advanced Technology Center, CLEO: Applications & Technology 2013 Program Chair

This year’s CLEO Conference, sponsored by APS/Division of Laser Science, IEEE Photonics Society and the Optical Society features an expanding Applications & Technology Program focusing on the core areas of Biomed, Energy, Industrial and Government/National Science and Security Standards.  Tom Giallorenzi, OSA’s Science Advisor interviewed Iain Mckinnie, Program Chair, Applications & Technology to delve further into some of this year’s hot topics.

Tom Giallorenzi: Can you say a little bit about technology transitions that this meeting is fostering?

Iain McKinnie:      “………there are many great examples in the Applications and Technology conference that you can see, including quantum cascade lasers.  We have a plenary talk this year which we’re very excited about by Dr. Kumar Patel from Pranalytica who is also a professor at UCLA.  And he’s going to be talking about how those quantum cascade lasers – now room temperature and multi-watt lasers in the midwave and long wave infrared region – are impacting applications from civil aircraft defense via countermeasures, through to trace gas detection for a range of commercial security  and environmental applications.  So that’s one capability that’s transitioning.

There are many more.  In the energy area, we’re looking at increasing transition of broadband nitride semiconductor materials in solar cells and in extending the spectral range of LEDs down into the UV region from the visible region. We’re also seeing increasing transition of ultrafast lasers, which continue to enable advances in manufacturing from the macro to the micro down to the nano scale.  ……. I think that we keep the wow factor in the conference also, and that comes in via big science; with some of the facility class laser systems: electron beams being used to generate extremely short bursts of intense light, and being used to generate extremely broadband, broad spectral access from the UV right out far into the infrared region.  Also, we have a big emphasis this year on the National Ignition Facility and the latest progress that they have achieved in the extreme high field regime.  So, you know, I think as well as things that could have mass market applicability, it’s important that we keep our finger on the pulse of the really impressive landmark advances at the unique and high power end.

Tom Giallorenzi: Can you say a few words about the special symposia?

Iain McKinnie:      One thing we’re very consciously focused on in 2013 at CLEO A&T is to bring in a number of special symposia which we believe represents a pretty broad suite of the application space for lasers that’s emerging.  I mentioned already the symposium related to the national ignition facility.  We have a number of others.  One that we’re excited about at the extreme other end of the scale is a lab on a chip symposium this year where we’re really taking advantage of advances not only in laser and LED sources, but also in microfluidics and nanotechnology and a whole lot of related applications to really take the pulse of that field and get a sense for how lab on a chip is advancing.

Beyond that, we also have a special symposium that’s looking at how the advances in sources are impacting biomedical applications more broadly.  That’s looking at advances in, for example, multi-modal imaging –  and looking at how relatively new sources like super continuum sources are being transitioned over into the application space.  And that’s a good example where there’s a need for those sources to be quieter and so that then flows back to the laser developers to really work on tailoring those sources for those kinds of applications.  I see biomedicine really being one of our significant growth areas in applications in technology in the coming years. 

 For more information on CLEO: 2013, visit www.cleoconference.org.

Feb 16

This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.

To probe new scientific frontiers, we need new technology. On the other hand, the advance of the technology relies on the solid scientific foundation. Countless examples have shown us that science and technology evolve together to give us wonders and a better understanding of the universe and nature. Looking back at 2012, similar stories happened in the laser and optics arena – Lasers are extending the working wavelengths into shorter (X-rays) and longer (THz) domain and probe new scientific frontiers. With this advance, we can have a better grasp of our nature.

Femtosecond X-ray free electron lasers, the most established source to generate “coherent (laser-like) X-ray”, relies on a gigantic synchrotron. In brief, a bunch of high-energy electrons from the synchrotron is sent into a long tunnel made of magnets. The tunnel, often more than 100 meters, is called undulator.  The magnets are arranged in a way such that they create an alternate magnetic field to wiggle the electrons and force them into emitting X-rays. The wiggles are tuned to the wavelength of the X- ray and creating a feedback mechanism – this radiated X-ray acts on the electrons, concentrating them into smaller and tighter groups, and makes the electrons emit more X-ray coherently. Apparently, it is very similar to normal lasing scheme, in which the radiation in the cavity induces more radiations. The main difference is that in the case of X-ray, there is no cavity since no reflective mirrors are available in this wavelength region.

What excites us in 2012 is that this “new light” gives us a better way to elucidate the secret of our living nature. It is used to probe the structure of the proteins: Continue reading »

Jan 29

By Dominic Siriani

Diode lasers found their place in the world many years ago. Early on, they let us listen to our CDs and later watch our DVDs. They are in our little laser mice and our room-sized supercomputers. They are largely responsible for the telecom boom, putting the internet at our fingertips, and so help me reach all who read this blog. Like the transistor that preceded it, the diode laser has established itself as a cornerstone of modern technology. So this begs the question: what’s next?

 Well, the natural thing is to think bigger. I’m not saying make these lasers physically larger. One of them is smaller than a strand of hair from my head, and we like them that way. But the age-long question is how we can get even more out of these devices. How can we expand their sphere of influence to areas that require very high optical powers, while still maintaining their excellent efficiency and very small size?

Part of the answer has been known for a very long time, probably just about as long as the diode laser itself has existed: two lasers are better than one. By combining the emission from multiple diode lasers, you can still keep things pretty small and efficient but scale up to much higher powers.

 Until quite recently in the history of diode lasers, this strategy really wasn’t so essential. Advances in materials growth and processing, development of new device structures, and a variety of other ingenious ideas led to the gradual improvement of diode laser power and efficiency over time. We might now be in the midst of a change. I wouldn’t go so far as to say that we’ve gotten to where, like the microprocessor, we’ve hit a physical limit for conventional scaling methods. However, advancements have become challenging enough that it’s very helpful to utilize more weapons in the scaling arsenal.

DSo, the idea is pretty straightforward: gang together a bunch of diode lasers to get to your desired higher power. In practice, there’s some subtlety to it. For example, do you want to have a high quality beam or can you tolerate low beam quality? Do you need emission at a single wavelength, multiple wavelengths, or does it not matter? Diode laser beam combining methods exist for all these scenarios.

Consider, hypothetically, that you need to dump a whole bunch of optical power into a small area. Well, then you probably need good beam quality. But if you can tolerate (or even use) multiple wavelengths,then you can use a

Wavelength Beam

Illustration of wavelength beam combining (like running a diffraction grating in reverse).

technique known as wavelength beam combining, where, for example, lasers operating at regularly spaced frequencies are combined using a grating. Other techniques, like single-frequency phase-locking and incoherent beam combining, have their own sets of merits and application areas. These arrays really allow you to think of exciting niches for diode lasers: high-power solid-state laser pumping, laser welding, lidar, and the list goes on. And each one of these applications can require a different diode laser array type and beam combining technique. And, as one might imagine, there is not just one method to implement a particular technique. That’s great news: we’ve got all kinds of stuff to research!

This is a rather shallow overview of the importance, methods, applications, etc. of diode laser arrays and beam combining. And I really didn’t even touch on all the challenges! Luckily, there’s an entire symposium dedicated to high power diode laser arrays at the upcoming CLEO meeting. There you likely can learn more about the specific beam combining methods, where they’re useful, and what the state-of-the-art is. It’s an ever-evolving field, so it’s sure to be an exciting set of talks, pushing the envelope of what we can imagine diode lasers can do.

 Disclaimer: Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the United States Government and MIT Lincoln Laboratory.

Dec 25

Demonstration of phase gradient microscopy in thick-tissue with back-illumination suitable for endoscopic integration. (a,c,e) amplitude images (b,d,f) phase gradient images of mouse intestinal epithelium. From T. ford, J. Chu, and J. Mertz, Nature Methods, 9, 1195 (2012). Jerome Mertz, Boston Univeristy, among other biomedical researchers, will be presenting latest breakthroughs in endoscopic imaging during invited talks at CLEO 2013 Applications and Technology: Biomedical.

This post originally appeared on Jim’s Cleo Blog and is reproduced with the author’s permission.

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.

Stomach tissue from my own recent upper-GI endoscopy using a conventional commercial endocscope.

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.

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?

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 efficient, high-resolution nonlinear endomicroscopy and  the other from Chris Xu’s lab of Cornell University which piggy-backed wide-field one-photon imaging with high-resloution two-photon imaging in the same device 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 two-photon imaging for targeting tissue and subsurface precision microsurgery  through athermal ablation. Last year’s CLEO also hosted an invited talk by Brett Bouma, pioneer of Optical Coherence Tomography (OCT), on translating OCT into GI endoscopy.

This year’s invited speakers in CLEOs Applications and Technology: Biomedical 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 just published in this week’s  Nature Methods. 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 in vivo 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.

Continue reading »

Oct 22

This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.

It is an understatement when we describe nature as the most talented painter. In fact, she is not only the greatest artist, but also the most renowned scientist, in essentially all aspects. Her scientific achievements are found everywhere. For example, today, much of our knowledge in the field of bio-photonics is just a re-discovery of what she has done (Another interesting topic which relates the evolution to optical science can be found here).

Many of the astonishing color patterns we found in the insect kingdoms are manifestations of nanometre-scale architectures. These architectures are collaborative works of cells. Those cells cooperate together to create optical effects we widely apply in modern photonic science. For instance, butterflies have cells structures that look like multi-layer reflective coatings on their wings. Depending on the thickness of each layer, different colors present vividly. Same tricks have been adopted and perfected by many shiny beetles. As shown in figure 1, enchanting colors on the surface of the insects are precisely the magic of multilayer structures. The layers are mostly composed of thin parallel sheets of chitin (secreted by the epidermis and often interspersed with other organic components). These layers differ in refractive index. And again, depending on the spacing between these layers and their indices of refractions, different colors can be reflected. Furthermore, some insects have arrays of very fine elements, known as nipple arrays, which look like micro lenses with subtle variation of index of refraction, to reduce reflectivity in their compound eyes and enhance collecting the light from the environment. Nature did create optical science way before mankind stole fire from Prometheus!

Figure 1. (a) A presentation of simple cuticular multilayer reflector. (b) The cross section of a cuticular reflector. (c) A colorful buprestid. (d)-(f) Different structures of cuticular multilayer reflectors commonly seen in insects. Courtesy of A. E. Seago, P. Brady, J-P. Vignerson, and T. D. Schultz in J. R. Soc. Interface 6(supp2) S165–S184 (2008).

Continue reading »

Aug 28
This post originally appeared on CLEO BLOG by Frank Kuo and is reproduced with permission from its author.

     If you think metamaterial has only “invisible cloak” and/or “negative index of refraction” in her hat, think again. Researchers from the school of engineering and applied science at Harvard utilize a powerful feature of the metamaterial to create ultra-thin and flat lens that is diffraction limited. They also create a flat axicon as another example when pioneering in this field (A quick glimpse on the Axicon: A lens with a flat surface on one side, and a conical shape on the other, has the ability to focus a Gaussian beam into a Bessel beam at the focal region, and create hollow ring beam shape in the far field).

     To focus light, we need to create a converging spherical wavefront, or at least, a wavefront that is converging. To do so, we need to introduce different phase retardation on different portion of the incident light. A spherical lens does so by letting the light pass through different amount of material. For example, when light is passing through the center of the lens, it lags behind compared with that passes through the edge of the lens. As a result, there is a phase difference between them. This phase difference, or phase retardation between them, produces a converging wavefront. However, when a plane wave like light passes through a spherical lens, it suffers from spherical aberration. That is to say the spherical lens does not produce a perfectly converging spherical wavefront which is required for the light to focus tightly. The light exiting from the edge of the lens suffers stronger deviation. The best way to solve this so far is to use an aspherical lens to correct this imperfection.

Continue reading »

Tagged with:
Aug 16

Many of us have heard the popular expression “curiosity killed the cat.” The saying is used to warn of the dangers of unnecessary investigation or experimentation. However, less widely known is the rest of the phrase. In full, it reads “curiosity killed the cat, but satisfaction brought it back.”

The full saying recalls the significance of a curious mind. Indeed, curiosity has been listed as an important trait of genius and an examination of many of the intellectual giants of the past, such as Albert Einstein, Thomas Edison, and Leonardo DaVinci, reveal that common among these great minds is the curious nature of their character. In fact, it was Albert Einstein that said,” I have no special talent. I am only passionately curious.”

Curiously (pun intended) a Great Britain report on the common characteristics of physicists published in 1993 by a group of scientists assigned a host of adjectives to the profession, but curiosity was not listed as one. However, it is hard to imagine that individuals who gravitate to physics are not driven by their curious nature. I need only look to my father, who obtained his doctoral degree in physics, as a case study on the topic. My father was possessed with constant curiosity, which resulted in use of his spare time to continue his probing quest for knowledge. Often, after working a full day, my father would, for curiosity sake, prepare and solve formulas in his basement office and devour cover to cover every issue of Physics Today. While my father knew attempts to share his curiosity for physics would fall flat on his daughters, he made sure to impart on his girls their need to cultivate an inquiring mind by exploring the world and what it has to offer. True to his nature, family trips were made lengthy by a desire to ensure that we stopped at every historical landmark whether on the path or not to our destination.

My present position has me mingling with scientists like my father on a regular basis at scientific conferences. In my interaction with these individuals I find their personal characteristics to widely differ. That being said what shines through is the healthy curiosity that our conference participants bring with them to CLEO programs and the like.

My next conference of this type has me in San Jose, CA where along with the hundreds of impressive speakers on tap to discuss the latest research in optics and laser science, there will also be lots of attractions to explore in sunny San Jose, CA. I hope attendees take advantage of that curious nature to not only enjoy pioneering research but also the host of available attractions in the area and nearby San Francisco.

May 10
 

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.

The panelists from Tuesday’s 2:00 pm Market Focus, Defense: Laser Interrogation for Standoff Detection of Hazardous Materials, presented the audience with a difficult problem to which the U.S. Department of Defense is allocating many resources and substantial funding:

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)

 

May 10

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 sessiona 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.

Continue reading »

preload preload preload