Event photos and video links
SPIE Newsroom articles by Photonics West authors
Thursday 7 February
Wednesday 6 February
Tuesday 5 February
Monday 4 February
Sunday 3 February
Saturday 2 February
Thursday 7 February
What a great week!
Photonics West ended under sunny skies in San Francisco -- a reflection of the all-around positive experience reported by technical and exhibition participants alike. Total registered attendance, at 20,737, was up more than 2% from last year, the exhibitions were larger, and there were more papers in the technical program. (Learn more in the SPIE press release.)
Exhibitors stressed the qualitative difference even more than traffic numbers, reporting that booth visitors were more focused on what it was they were looking for.
"This is the best Photonics West I've seen in 10 years -- and they all are great," said Kerry Van Iseghem, co-founder of Imaging Solutions Group.
A coffee shop near the Moscone Center still sported one of many welcome signs for Photonics West attendees at week's end.
Government initiatives, opportunities for growth
Countries and regions that foster the photonics industry are leading in the global economy and creating jobs, noted SPIE CEO Eugene Arthurs in at talk after Thursday morning's exhibitor breakfast. The National Photonics Initiative, sparked by the U.S. National Academies study "Optics and Photonics, Essential Technologies for Our Nation" and being driven by SPIE, the IEEE Photonics Society, LIA, OSA, and APS, offers renewed impetus for growth in the U.S.
See more news in the Thursday edition of the Photonics West Show Daily.
Wednesday 6 February
So many choices!
With the LASE plenaries, Sustainable Technology Panel, exhibition, and numerous conferences happening, it's hard to decide what to do first!
Lasers: surfing, cutting, welding
First speaker in the LASE plenary sess was Wim Leemans from Lawrence Berkeley National Labs who presented his work on the acceleration of particles using laser generated plasmas. Leemans explained how electrons effectively "surf" on the wake of the laser pulse in order to achieve rapid acceleration within distances of only centimeters, as opposed to the multi-kilometer long accelerations that exist today. This analogy was so important that Leemans told the audience "if you remember nothing else of my talk, or if you want to sleep through my talk, dream of surfers."
Next up, Mark Wegener from Karlsruhe Institute of Technology presented work on a variety of direct laser writing techniques used to create novel nanoscale structures, including quasi crystalline structures with special optical properties. The cutting edge techniques he described eliminated the traditional limitations of structure height, increased the write speed of 3D writing and achieved a resolution almost twice as high as other writing techniques. One technique he explained involved the focusing of not just one, but two lasers, one with a donut shaped focus that could de-excite the area surrounding the focus of the writing laser in order to increase the writing resolution.
From Faurecia Autositze GmbH, Geert Verhaeghe described how his company is using remote laser welding to increase their manufacturing quality and efficiency. Faurecia is a large manufacturer of automotive seeding, supplying many major car companies like BMW with light weight high quality seating. By using solid state laser systems manufactured by Trumpf, combined with fiber delivery system and a robotic arm, they have been able to reduce the weight of their product and increase their weld strength while decreasing manufacturing time.
Defense downturn balanced by growth in other areas
If there was a consensus to be had at the Executive Perspectives panel on Wednesday afternoon, it might be summed up as "some good, some bad."
High-level executives from several photonics corporations reviewed their companies' experience in the year just ended. Battling against an uncertain defense market due to U.S. budget issues, Dennis Werth, vice president of Newport Corporation, said after a down year in that sector, "we're hoping we've reached the bottom."
Edmund Optics CEO Robert Edmund, who reported a flat year across all sectors after two years of growth, expressed some surprise that the defense sector for his company had done as well as it did. "The decline was not really as big as expected," he said. Several panelists attributed this to increases from other countries' defense spending, with the realization that the United States may no longer "have their back" due to its own challenges. "It's good for business, but bad for other things," Edmund said.
Werth said that many technologies developed for the military had matured enough to "get out of defense in into consumer applications." He cited forward-looking IR systems as an example. Newport reported double-digit growth in industrial applications as well as the life and health sciences; meanwhile research applications and semiconductor processing were down 8% and 10% each, he said.
Dirk Rothweiler of Jenoptik said that his company's industrial metrology division had its best year ever in 2012, crediting "not revolutionary steps but evolutionary steps to address economies of scale." Most of the company's growh was in North America and Asia, he said.
Christof Lehner of Trumpf said that industrial laser cutting remains strong, and tools for EUV technology in semiconductor manufacturing have shown "tremendous growth."
Linda Smith of Ceres Technology Advisors said that the number of transactions involving photonics company acquisitions and mergers doubled in 2012, and that typical sales were to "strategic buyers," a trend she called good for the industry. "It gives [the acquired company] access to capital and distribution, and helps the technology develop. Maybe the growth wasn't organic, but I think it's good," she said.
In response to a question about employment as a result of reported growth, Lehner said that Trumpf has increased employees on the engineering side, but not so much on the production side. He was surprised to find how difficult it is to find trained people for production work in the United States, he said. Rothweiler echoed that, saying Jenoptik is "looking for hands on production floors.
David Marks, CEO of Qioptiq, was more blunt, saying that increasing efficiency is key to making money for shareholders. "Everybody is trying to make more things with less people, that's the truth. We're trying to get more out of what we've got."
A bright spot in the view of most panelists was the biomedical area, which Turan Erdogan of Idex Optics and Photonics pointed out is driven differently from most market sectors. Government and academic research figure heavily into what instruments will be in demand. Manufacturers "look at research papers to decide what goes into their next instrument," he said.
One factor inhibiting even more robust growth, he said is "inertia in the medical community to adopting new technology." Sometimes available technology is delayed five to 15 years before it is widely in use. "We've got to wait for a generation of doctors to disappear and a new one to come up," he said.
And the winners are ....
Winners of the 2013 Prism Awards for Photonics Innovation were announced at a gala banquet honoring inventions by 10 companies using photonics to improve our lives. Read the SPIE press release and find out who won.
Startup Challenge: more winners!
The top three winners in the increasingly competitive Startup Challenge were named after final pitches were heard on Wednesdary afternoon. From left, winners are Arun Chhabra (pictured) and Erik Klaas (co-founders, 8-tree): first place for "fastCHECK: a revolutionary 3D surface inspection system that is amazingly fast, accurate and easy-to-use"; Ryan Denomme (founder, Nicoya Lifesciences): second place for "Compact, low-cost, high-performance optical biosensors for point-of-care diagnostics"; and Frank Palmer (CEO, Cold Steel Laser): third place for "Remote image-guided endoscopic surgery (RIGES) platform." Read more details and watch the winning pitch on video.
No ties, plenty of networking
Tony Akl, a grad student in optical bio-sensing at Texas A&M, lets loose at the No-Ties Student Social at Jillian's Billiards Club.
See more news in the Wednesday edition of the Photonics West Show Daily.
Tuesday 5 February
Bigger than ever: the Photonics West exhibition!
Aisles were crowded from morning until closing time on the busy first day of the Photonics West Exhibition. With 1,238 exhibiting companies, the event is bigger than ever. Exhibitors had good things to say about quality as well.
“Photonics West is the place to meet everybody we need to,” said Robert Miller, Business Manager, OE & PV, at EMD Chemicals. “Because we’re not just a photonics company, it’s very important to be able to expand our horizons, and with so many diverse companies here, it really fits our needs.”
“We’re really excited this year,” said Dave Creasey, OEM Manager, Ocean Optics. “We’ve created a fun, innovative new booth for Photonics West. And we’ve been so busy that I haven’t had time for lunch.” of Fellow of the Society for 2013. New Fellows receive their award plaques at various meetings throughout the year. (See more photos in the event photo gallery.)
Quantum optics: a new toolbox
Tuesday's OPTO plenary kicked off with Markus Aspelmeyer of the University of Vienna describing recent developments in quantum optomechanics, where quantum effects are being put to use driving macro systems. "Sensing based on purely classical mechanical oscillators has now become amazingly accurate, able to sense displacements of attometers and masses measured in yoctograms [10-24g]," he told the audience.
The approach potentially provides a new toolbox of techniques for engineers to use, in applications where the manipulation of photons feeds through into action on the nano-, micro- or macro-scale. In some cases a single universal coupling system might be feasible, exploiting the effects across the full breadth of this size range. This could allow engineers to make good use of quantum phenomena previously thought to be undesirable, and turn them to advantage.
Ultrafast lasers and light-matter interactions
Ultrafast laser micromachining and light-matter interactions were the topics in Tuesday morning's "Frontiers in Ultrafast Optics" conference, part of the LASE symposium.
Glass machining has long been identified as a likely industrial application for such lasers, and in an invited paper (8611-44) Electro Scientific Industries showed rapid-fire machining of Corning's Gorilla glass, dicing up large sheets of the rugged material.
Regina Moser from the University of Applied Sciences in Munich, presented work that could increase the efficiency of large industrial printing machines, by reducing absorption losses from the titanium foil used as vacuum windows (8611- 45). The printing machines generate electron beams to dry freshly printed colored ink, but the titanium foils, which cannot be rolled to thicknesses of less than 15 microns, create absorption losses that reduce overall system efficiency. Moser showed a picosecond processing technique that reduced the foils to one-third of their original thickness, representing a huge potential reduction in absorption losses.
Also from the University of Applied Sciences, Matthias Domke showed the effects of confined heating of molybdenum by focusing femtosecond light onto a sample of the metal bonded to a layer of glass (8611-46). That created enough pressure to blow off a circular section of the sample from the glass. As Domke explained, the effect was discovered during processing of photovoltaic cells, and was so unique that it merited an independent study of its own.
Kasey Philips from Harvard University (8607-14) showed how titanium samples could be doped using femtosecond laser processing, with individual studies of magnesium, nickel, and chromium. The goal, Philips explained, was to find a way to increase the absorption of titanium for applications.
Alumni of the University of Arizona College of Optics Sciences packed the house for a reunion in the Hilton Hotel. From left, Jack Jewell of TJ Optics, Ric Shimshock and Linda Lingg of MLD Technologies, and SPIE Past President Eustace Dereniak.
Members at the top
SPIE Members enjoyed the view from the 46th floor at a reception in their honor at the Cityscape lounge. See more photos in the event photo gallery.
Networking before the MOEMS-MEMS and LASE poster session
See more news in the Tuesday edition of the Photonics West Show Daily.
Monday 4 February
MOEMS-MEMS: nano-optics coming of age
MOEMS-MEMS plenary speakers focused on technologies that are pushing the envelope and catapulting forward the capabilities of current MOEMS and MEMS.
Bozena Kaminska of Simon Fraser University shared her work to progress nanoscale production. By reducing difficulty and cost of creating nanohole arrays (NHAs), increasing stability and reproducibility, and finding fabrication methods that are compatible with the semiconductor industry, they have been able to create some novel nano-structures that can be easily manufactured at rates 3X faster (and 3X less expensive) than the current state of the art.
Some interesting applications that they are pursuing with this technology involve solar cells, creating organic photovoltaics, with an approximate 4X increase in power conversion efficiency over conventional ITO electrodes, and also new levels of security via anti-counterfeiting measures such as holograms using NHA to provide authenticity of documents and currency. Her goal is to bridge nanostructures into a commercial space where they can be produced at larger volumes with lower costs.
Kaili Jiang of Tsinghua University presented on "Super-aligned carbon nanotubes (SACNTs): a road toward real applications." After spending 10 years studying SACNTs, he has been able to go from an idea of serendipity to controlled batch growth to real productss. Among the intriguing applications he demonstrated was a transparent flexible stretchable loudspeaker and flexible SACNTs touch screens intended to replace expensive and brittle ITO screens -- just a few of many potential applications he envisioned.
New Fellows: congratulations!
At a luncheon for nearly 200 SPIE Fellows, Joshua Silver, CEO of the Centre for Vision in the Developing World (at right), demonstrated the "instant prescription eyewear" that his organization hopes to bring to millions of people in the developing world who have no access to vision correction services. Silver's interest in adaptive optics lead to his idea for adaptive lens eyeglasses that would work in the way our eye-brain adaptive optical system works and allow the user to adjust them as needed.
Adjustable glasses can be used with all refraction techniques including the process of self-refraction. Using a number of different lens technologies, such as electrowetting, electroactive, and fluid-filled lens technology, the user can turn a dial on the eyepiece to adjust the lenses to correct their own refractive error. The techniques and clinical trials for the adjustable glasses are still in their infancy, but they are already in use by 50,000 people in 20 countries.
His presentation was part of an award ceremony for 29 of the 69 SPIE members who have been promoted to the rank of Fellow of the Society for 2013. New Fellows receive their award plaques at various meetings throughout the year. (See more photos in the event photo gallery.)
Quality and balance: Women in Optics
About 100 optics students and early-career professionals participated in a Women in Optics roundtable discussion on the challenges faced by women in science and technology.
A panel of scientists moderated by Michelle Xu (UC Berkeley) answered audience questions about starting a career in optics as well as the special challenges of juggling family life with a career in academia or industry.
How can a PhD student or post-doc find a research area that's ripe for innovation and will spur her on her career? "Look for problems in your own PhD research and go in that direction" to solve those problems, advised Kristen Maitland (Texas A&M University).
Angela Seddon (Nottingham University) agreed with other panelists that women must work extra hard to make the most effective use of their time in the lab, office, or classroom so that they can spend quality time with their family.
"You give everything to your work and you give everything to your child," Seddon said.
Along with Seddon and Maitland, panelists included Mona Jarrahi (University of Michigan), Jennifer Ellsworth (Lawrence Livermore National Lab), and Desiré Whitmore (UC Berkeley).
Making it happen: optics and photonics clusters
The efforts of optics and photonics clusters and industry groups around the world to promote and advance the technologies were celebrated at a reception hosted by SPIE. Several of the groups are represented on the Photonics West Exhibition floor, with impressive booths showcasing their regions' companies, research institutes, and activities.
Photonics West welcome reception: Photonics in Motion!
Nearly 3000 attendees enjoyed food and drink, networking, and a time to socialize in a casual atmosphere at the Photonics West Welcome Reception. RobotsLAB US Inc. wowed the crowd with dancing robots. View Welcome Reception photos in the event photo gallery.
Sunday 3 February
BiOS Expo quality 'high, as usual'
Exhibitors reported that Saturday's strong booth traffic continued to hold up on Sunday at the BiOS Expo, with companies happily continuing to write new orders."Even on Sunday afternoon, despite the Super Bowl, we had a good audience," said Uwe Ortmann, Head of Sales and Marketing at PicoQuant. "Quality was high as usual at BiOS."
Ernie Sirkin at Akela Laser had positive feedback about the number of leads their booth saw, reporting that traffic was much higher than in years past.
The BiOS Expo gives researchers a chance to meet with suppliers of lasers, lenses, and other components for a variety of biomedical applications. See more photos in the exhibition photo gallery.
Retinal prosthesis at final stages of FDA trial
A retinal prosthesis to return sight to people with moderate to severe pigmentosa is in the final stages of FDA clinical trials, as reported by Lyndon Da Cruz et al in a BiOS session Sunday (8615-6).
The Argus II by Second Sight assists patients blinded by retinal damage that prevents the conversion of incident photons into electrical signals for processing in the brain.
Argus II comprises an implant that attaches directly to the eye, and a modified set of eyewear which works in tandem with the implant. The implant features an electronics case and antenna mounted to the outside of the eye, and an array of electrodes attached directly to the retina. The electrodes artificially stimulate the retina and can be switched individually like pixels in a screen. The brain then processes the "image" electrically projected onto the retina.
Already available in Europe, Argus II is being FDA-tested for improving patients' ability to perform visual tasks, and the effect it has on their quality of life. It has been able to improve tasks such as locating a door in a room by almost a factor of two, and has even enabled patients to perform otherwise impossible everyday tasks, such as sorting dark and light colored socks.
In a remarkable video, one subject was able to walk down the street and halt when another pedestrian crossed his path, demonstrating the real-world utility of the device. Other possibilities that are being explored include face detection and text finding for conversion to visual brail.
Of 26 subjects in the study, 20 showed an improved quality of life, with the remaining six having a neutral response to the implant.
Bench to marketplace
A self-proclaimed "accidental serial entrepreneur" and the CEO of a new company that works as a matchmaker for optics inventors and existing infrastructure and market channels were among the speakers at a professional development workshop Sunday for students and early career professionals attending SPIE Photonics West.
"The odds of getting tenure (at a university) and becoming a successful entrepreneur are about the same," said Peter Fiske, CEO of PAX Water Technologies, so photonics researchers who have an idea with commercial potential should develop their business and leadership skills and think about a career as an entrepreneur.
Speaking about a career path "From Bench to the Marketplace," Fiske was joined by Bill Parker, CEO of Creative Microsystems Corp., and Jason Eichenholz, CEO of Open Photonics Inc.
Parker has been involved with eight startups and is the inventor of the Plasma Sphere, a light sculpture with plasma that he invented when he accidentally left a valve open during an experiment with gas in a glass ball.
Eichenholz discussed several ways young inventors can get financial help to take their ideas to market, including applying for grants and technology prizes, crowd-funding, and a grant program that Open Photonics has to bring companies with development budgets together with promising innovators. He recently wrote about open innovation in photonics in SPIE Professional magazine.
"Bench to Marketplace" presenters (from left) Jason Eichenholz, Peter Fiske, and Bill Parker.
The event preceded a Student Chapter Leadership Workshop; see photos in the event photo gallery.
Rochester: together again
Xi-Cheng Zhang (below), director of the Institute of Optics at the Universitiy of Rochester, welcomed a large crowd of alumni and friends to an annual reunion reception at the Westin Hotel. Zhang's update on the institute's accomplishments over the past year included numerous prestigious awards and milestones for faculty and alumni, updates including a new program in optical engineering, and acknowledgement of the contributions of the impressive number of startup companies that have spun out of UR research.
Optics strength in Wuhan
Photonics West provides many opportunities for meeting with colleagues: from left below, Lin Lin and Vice President and Cheung Kong Professor Qingming Luo of the Wuhan National Lab for Optoelectonrics of Huazhong University of Science and Technology (HUST) met with SPIE President Bill Arnold and others. The optical engineering program at HUST was recently ranked number one out of 95 by the Chinese Ministry of Education.
Saturday 2 February
Getting started: BiOS conferences and Expo
The week got off to a flying start with the several BiOS conferences in session, and the opening of the two-day BiOS Expo. With more exhibiting companies and more technical papers than ever before, energy was high in both the conference rooms and the exhibition halls.
Bio-inspiration was the topic of one of the week's first talks.
The design of digital camera systems is predicated on the use of a flat digital image detector of millions of pixel elements. Because the image plane is flat, multiple (and sometimes complex) lens elements need to be designed to produce a well-focused image over the specified field of view onto this flat plane. A single convex lens produces a well-focused image over a curved field known as the Petzval surface. If the detector plane could be curved, digital camera systems could be made much less expensively and much smaller.
In "Digital cameras in bio-inspired designs: from humans to flies" (8598-1), John Rogers (Univ. of Illinois, Urbana-Champaign) explored the development of methods of producing curved optical detector arrays. The process employed is to produce the pixel array on a thin silicon substrate and etch around the pixel elements leaving narrow ribbons of interconnecting electrical lines. The resultant sensor is then bonded to a pre-stretched elastomer base, with the bonding sights at the pixel elements only.
When the elastomer is relaxed all of the bending is taken up by the thin interconnecting lines, so the stress on the image elements is small and they perform reliably. This process was used to make small round image arrays on many different shapes, from spherical to pyramidal. Simple lenses (single convex) were used to build camera systems which performed with well-focused spot sized over the design field of view and were competitive with much more complex camera systems.
Optogenetics: shedding light on depression?
A standing-room-only audience heard Karl Deisseroth of Stanford University describe in his keynote talk (8586-1) the strides now being made in that field and some of the implications for the understanding of behavior.
Current advances exploit developments in both the biochemical markers added into neural circuitry, and the optical methods used to then activate or regulate them -- the twin principles on which optogenetics is based.
Some of the most fascinating work involves mapping the neural dynamics accompanying the manifestation of certain depressive symptoms, a potentially profound area of study.
Once the neural circuitry involved in depressive states is mapped, it might then be possible to affect those mental states by changing the behavior of the neurons. Deisseroth described how similar optogenetics approaches were now shedding light on the influence of dopamine on risk/reward behavior, and on the significance of certain neurons to cocaine addiction.
"It is still early days with a great deal left to understand about the causal dynamics involved in these states of mind, but it is a very interesting area," he said.
The first poster session of the week allowed attendees and authors to network directly, and to discuss their work.
In all, nearly 2,000 presentations will provide the latest information on biomedical optics, diagnostics and therapeutics, biophotonics, molecular imaging, optical microscopy, optical coherence tomography, and optogenetics -- a strong showing all around, with nearly 4,500 papers in all four symposia.
BiOS Expo: 224 companies strong
The BiOS Expo floor was crowded with attendees learning about the latest biomedical optics components, products, instrumentation, and applications. See more photos in the exhibition photo gallery.
Steve Smith of Pixelteq by Ocean Thin Films had a standing room only crowd to see examples of how multispectral cameras and sensors empower innovative biomedical devices and instrumentation across the UV, VIS, and NIR/SWIR ranges.
Hot topics: Saturday night place to be!
Once again, the BiOS Hot Topics session proved the Saturday-night destination of choice as hundreds of people packed the room to hear eight speakers in a session moderated by Sergio Fantini of Tufts Univ. (at right).
Speakers each presented their audience of optics and photonics experts with the challenge of further integrating the technologies into clinical practice, along with updates on applications such as surgical robotics and ultrasound, for treating stroke, cancer, and numerous other conditions.
Symposium chair Rox Anderson (Wellman Center for Photomedicine, Massachusetts General Hospital, and Harvard Medical School) at left below, with SPIE CEO Eugene Arthurs) framed the event perfectly at the outset, thanking the audience for their efforts to use biomedical optics and biophotonics "to help."
See photos of the speakers in the event news gallery.
Optogenetics and hybrid-optical control of cells
Ernst Baumberg (Max Planck Institute) led off with a talk on optogenetics, a relatively new field that uses light to signal functional changes in the activity of individual neurons in living tissue. The cells of the neurons express a protein, channelrhodopsin, which acts to light gate ion channels. By either the absence or presence of light (or light of specific wavelengths) nerve cells can be inhibited from firing. This capability can be used to map the motor functionality of the brain or to control the functionality of other cells.
As examples. Bamberg showed that this technique can be used to activate cells in the optic nerve for those who suffer loss of sight, or can be used to stop and start a beating heart in a small animal.
MEMs tunable VCSEL technology for ultrahigh-speed OCT
Ben Potsaid (Massachusetts Institute of Technology) noted that optical coherence tomography (OCT) is a powerful optical technique for volumetric scanning through material like living tissue and mapping the layers of cells within that tissue. However, in order to produce an image, the laser source needs to be swept across the sample in 2D fashion and the data must be gathered at high enough speed to create an image in a reasonable time. Initial implementations of OCT used time-domain techniques that limited data collection to 400 samples/second. The next advancement came with spectral domain OCT and improved the rate to 26000 samples/second.
Potsaid discussed a swept-source technique using a MEMs tunable VCSEL (vertical cavity surface-emitting laser) which improves on this speed by a factor of 50. The MEMS element is modulated at 600kHz over a range of only 1 micron, but that is enough to sweep the wavelength of the source which provides improved sensitivity and rate of scan. Multiple scans, of areas such as a human eye retina, can now be made between heartbeats. With Doppler techniques, the flow of blood can be mapped and used for disease diagnostics.
Patterened multiphoton photoactivation in scattering tissue by temporal focusing
Laser illumination of tissue produces a broad area of response as light is scattered in front of and beyond the focus region. Dan Oron (Weizmann Institute of Science) described how this can be overcome by using two-photon techniques where only the region of interest contains the two-photon response as the diffuse light is too weak in other regions.
Temporal focusing uses multiple pulses and changes the duration of the individual pulses so that their overlap at a specific location is limited in time. This combination of spatial and temporal focusing provides improved sensitivity which facilitates much longer depths of penetration in tissue. This technique was used to photoactively stimulate a single neuron through 200 microns of nerve tissue.
Clinical requirements for optical imaging in medical robotics
Over half a million surgeries out of 240 million performed annually are facilitated by medical robots, said Jonathan Sorger (Intuitive Surgical). The benefits of the use of robotics are related to the minimally invasive nature of their operation. They reduce bleeding, chance of infection and length of hospital stay. The robotic systems also provide a stable platform for imaging modalities used by the surgeons in the procedures.
However, the surgical environment presents many challenges to this instrumentation, such as motion of the subject, bleeding and the need for high positional accuracy. Sorger presented the motivation for more work in this field with the aim to increase the speed of operation, improve imaging in the surgical environment, and for the development of tissue characterization techniques to allow the identification of what is tumor, what is nerve, what is healthy tissue.
Camera-based functional imaging of tissue hemodynamics
Speckle imaging identifies changes in the subject through changes in the coherently summed light scattered off of the sample. As such, said Bernard Choi (Beckman Laser Institute), it is a good technique for monitoring changes in blood flow through tissue. One application area of interest is in the procedure to reduce port-wine stain of the skin using laser treatments. What is needed is the development of a real-time image guidance technique that identifies blood flow changes which prevent the complete reduction of the stain.
Another application area is in neurosurgery, where blood flow needs to be monitored during clamping, cutting and re-sectioning of blood vessels. Choi presented approaches using the speckle produced by structured illumination to map scattered and absorbed light in such a way as to produce a more absolute scale of blood flow and help reduce the uncertainty associated with current practice.
Multiwave approach to elasticity imaging for cancer detection
Acoustic imaging uses a phased array of ultrasound sources to focus a compression wave through the tissue. Mathias Fink (Institut ESPCI, CNRS) showed how a time-reversal analysis technique of the data from an array of receivers produces a reconstruction of the transversed medium and an image of internal subject. The time-reversal analysis is made possible because the speed of sound in most soft medium is fairly uniform.
The process is effective with image resolutions on the order of 1 mm, but it is slow and limited to 50 frames/second. An improved method uses shear waves through the medium which travel slower, but show much higher sensitivity to changes in material density. The shear waves are produced by developing a traveling focused spot in the sample, this produces laterally traveling shear waves which are monitored by high speed detectors. The result is a much improved signal-to-noise ratio which allows for faster scan times and more detail, both of which lead to improved specificity for detection of density changes due to diseases like cancer.
Functional optical imaging of the brain
Functional MRI (fMRI) is currently used to map brain activity by using tasked-based testing while the subject is in the MRI instrument. But this is not transportable to the operating environment and so other methods of identifying brain activity are sought. Joe Culver (Washington Univ. at St. Louis) described how diffuse optical imaging of scattered light is being investigated to produce a more portable brain monitoring system.
The technique uses correlations among multiple detector signals to map regions of brain activity. Current results show good agreement between fMRI and the diffuse scattering results. Pilot studies are under way in both the operating room and in prenatal care units. The issues under investigation are resolution, field of view and wearability of the instrument.
Photoacoustic flow cytometry: journey in the blood
Blood analysis is the mainstay of current medical diagnostics. However, a blood sample is typically a small amount, and concentration of the indicators of stroke, infection, cancer and other ailments is very low. Vladimir Zharov (Univ. of Arkansas for Medical Sciences) noted that while low cytometry techniques have the capability to make the diagnosis with much larger volumes of blood, they are not compatible with in-vivo procedures.
Zharov explored ideas of monitoring the characteristics of the patient's blood as it passes through his or her own veins. One possible approach would be to use magnetic nanoparticles which are targeted to attach to specific cells traveling in the blood. A strong magnet near a surface vessel would attract these particles to the edge of the vessel where they could be sampled by non-invasive techniques using lasers and the spectral response of the plasmonic nanoparticles. This approach could not only provide diagnostics, but also could be used to destroy the cancer stem cells and/or infected cells and provide therapy for the disease. Results showing specific cell identification inside bones and plants where presented indicating the current state of research.