Automated imaging of brain tissue, high-quality glimpses inside arteries

Major optics meeting features biomedical, homeland security breakthroughs

-- New Research Findings to Be Presented at 2003 CLEO/QELS Conference --

Washington, DC, May 21, 2003 ----- The Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS) 2003 -- a leading conference showcasing new results in laser science, quantum optics, and related fields -- will take place June 1-6, 2003 at the Baltimore Convention Center in Baltimore, MD. This year's meeting will feature breakthroughs in medical imaging, homeland security technology and many other areas, introducing the laser technologies of the future and the applications of today. With a prestigious history as the conference where the laser itself was launched, the meeting is jointly sponsored by the Optical Society of America (OSA), the American Physical Society (APS), and the Institute of Electrical and Electronics Engineers/Lasers and Electro-Optics Society (IEEE/LEOS).

MEETING PRESSROOM
A pressroom will be located in room 330 of the convention center from June 1 through June 5. Reporters wishing to register for the meeting should contact Colleen Morrison of OSA (202-416-1437, [email protected]). On Tuesday, June 3 at noon, OSA will hold a complimentary press luncheon featuring speakers on several topics that will be presented at the meeting. The speakers and location will be announced in a subsequent release. Reporters interested in attending the luncheon also should contact Colleen Morrison.

PLENARY SESSION
At this year's CLEO/QELS Plenary Session (4th Floor Ballroom of the Baltimore Convention Center, Wednesday, June 4 from 8:00 AM -10:30 AM), Jeff Kimble of the California Institute of Technology will discuss "The New Science of Quantum Information," a rapidly evolving field that promises to revolutionize computing, encryption, and communication by taking advantage of the unique properties of light and objects in the atomic and subatomic world.

Next, four pioneering researchers will celebrate the 40th anniversary of an invention that has already revolutionized our world - the semiconductor laser, the inexpensive lasers that are found ubiquitously in CD players, DVD players, fiber-optics communications, laser pointers and innumerable other products. The speakers worked for four separate labs that independently built these lasers in a thrilling race forty years ago. The Plenary discussion will highlight the monumental achievements of these individuals, investigate the road the semiconductor laser has taken to achieve commercial success and hypothesize on future applications of this significant technology.

NEWS BRIEFS: A PREVIEW OF NEW RESEARCH TO BE PRESENTED
With an all-time high of 1,644 papers submitted, an 18% increase over 2002, the CLEO/QELS technical program has never been stronger. This year's conference boasts 5 Plenary presentations, 12 tutorials, 3 poster sessions and 104 invited papers -- all focused on the most innovative research in laser technology. The following news briefs describe some of the many technical highlights at the meeting. For the full abstracts of any of these papers or for more information on the conference's program, visit the CLEO/QELS Web site at www.cleoconference.org or contact Colleen Morrison.

NEW IMAGING SYSTEM PROVIDES HIGH-QUALITY GLIMPSES INSIDE ARTERIES
In efforts that may soon change how doctors diagnose and treat coronary artery disease, Joseph Schmitt of Lightlab Imaging in Westford, Massachusetts, will present a research prototype imaging system that can provide high-quality inner views of blocked arteries. With pilot clinical trials underway during the past year, formal trials for FDA approval are scheduled to begin within 6 months. When diagnosing and treating coronary artery disease, physicians currently base most of their clinical decisions on what they see on the outside of a diseased artery. Specifically, they look at the degree of narrowing, or "stenosis," in an artery. However, conventional technology cannot take good images inside an artery, so it is unable to provide a detailed map or mechanical profile of the plaque that causes the blockage. The new system, incorporating several important technical advances in optical coherence tomography (OCT), employs all-fiber micro-optics (enabling tiny, high-quality imaging devices to be threaded through an artery); real-time, simultaneous acquisition of several types of optical data (polarization, Doppler, and dual-wavelength spectroscopy); and fast data acquisition, yielding images at 15 frames per second over a relatively wide scan diameter (7mm). Owing a debt to pioneering basic and clinical studies in intravascular OCT, Schmitt and his colleagues at Lightlab are now striving to make a commercial OCT system that can be reliably mass-produced at a reasonable cost. In testing the system, the researchers are working with numerous physicians, including cardiologist Dr. David Williams at Rhode Island Hospital. (Paper CMBB3, Intravascular imaging of atherosclerotic plaque with optical coherence tomography, Monday, June 2, 4:15 PM)

ULTRAFAST LASER AUTOMATES MICROSCOPIC-SCALE BRAIN IMAGING
In work that may accelerate progress in an important field of biology, researchers have experimentally demonstrated automated, layer-by-layer imaging of a brain tissue specimen. The automated technique can greatly accelerate data collection in histology, the study of cells and tissue at the microscopic level. Presently a manual process, histological imaging consists of freezing and mechanically slicing a tissue specimen of interest into thin sections that can be viewed with an optical microscope. An extremely important field, histology can help scientists determine the relationship between biological anatomy and function. Now, Jeff Squier of the Colorado School of Mines, and colleagues Phil Tsai and David Kleinfeld of the University of California, San Diego, have demonstrated, for the first time, that the whole imaging process can be automated by using a femtosecond laser beam, one that delivers ultrashort but powerful bursts of laser light. In their technique, the beam is used at low power (where it does no damage) to provide 3D images (through various optical imaging techniques) of a tissue specimen's first layer. This layer is typically 100 microns deep, about the thickness of a human hair. After taking this first image, researchers increase the laser intensity to the point where the light ablates (removes) the previously imaged layer. After the tissue layer is removed, the laser intensity is lowered again and used to image the next 100 micron thick layer. Repeating the process many times for subsequent tissue layers, the researchers can stack together the images to produce a complete three-dimensional picture of the tissue sample with resolution at the microscopic scale. In addition to demonstrating that the laser-ablation process does not harm the tissue layers for imaging purposes, the researchers have been able to image tissues without freezing them (which causes damage) and have also shown that the process works with very soft tissue -- a real challenge for standard histological processes. This technique may help speed up fundamental research on the brain, the organ that some medical scientists have called "the last frontier" of the human body. (Paper CMN3, All optical histology of brain tissue: serial ablation and multiphoton imaging with femtosecond pulses, Monday, June 2, 11:00 AM)

AN OCT ENDOSCOPE
Optical Coherence Tomography (OCT) has become a powerful diagnostic tool for many medical applications. In effect OCT provides "optical biopsies" that allow doctors to inspect tissues in vivo without the pain of conventional biopsies. In the past, OCT devices are generally limited to analyzing skin and other easily accessible, external portions of the body. Now a group of researchers from the Massachusetts Institute of Technology has developed an ultrahigh resolution OCT endoscope. The endoscope is equipped with adjustable focus and a rotational scanning element that allow the researchers to acquire minimally invasive OCT images of the esophagus and other gastrointestinal regions. With esophageal cancer as one of the fastest growing cancers in the United States, the OCT endoscope may provide a less invasive, first-step alternative to traditional biopsy for many. Paul Herz will describe the OCT endoscope on Monday, June 2 at 1:45 PM. (Paper CMU2, Micro-motor endoscope with adjustable focus for ultrahigh resolution OCT)

OPTICAL DEVICE SHOWS ABILITY TO CAPTURE, IDENTIFY SUSPICIOUS AGENTS IN AIR AND WATER Detecting and identifying single biological particles is challenging since these bioagents may randomly move and flow in liquid or air. At CLEO/QELS, Yong-Qing Li and colleagues at East Carolina University will present an optical sensor that can rapidly capture and identify individual biological and non-biological agents alike. Called the LTRS sensor, it works by combining a pair of optical technologies, known as laser tweezers and Raman spectroscopy. Laser tweezers capture microscopic particles in a fluid by using a tightly focused light beam. Raman spectroscopy can obtain a highly unique "fingerprint" for each substance by measuring the unique vibrations of its molecules. While the LTRS sensor has been previously shown to trap and identify biomolecules within single cells, the CLEO/QELS meeting will be the first occasion at which its developers demonstrate its feasibility as a sensor for fast, non-invasive identification of biological agents at the single-cell level. The researchers hope the LTRS sensors will find broad applications for rapidly sensing toxic bioagents (such as bacteria, spores, or viruses) in field sites (such as airports, sporting events and shopping malls) to aid in bio-terrorism defense. The instrument may also provide rapid and reliable clinical diagnosis of cellular disorders. In addition, the LTRS sensors can be used as a valuable tool to study cellular processes within single living cells or intracellular organelles and aid research in molecular and cellular biology. (Paper CMG5, Detection and identification of biological and non-biological particles using optical tweezers and Raman spectroscopy sensors, Monday June 2, 9 AM)

ULTRASENSITIVE GAS DETECTOR FOR INDUSTRY AND MEDICINE
A compact, low cost, portable, and rugged detector of carbon monoxide, carbon dioxide, and many other gases has been developed at Macquarie University in Sydney, Australia. Breath analysis of carbon dioxide and carbon monoxide is important for diagnosing a range of diseases including neonatal jaundice, asthma, peptic ulcers, and blood conditions, among other things. It is also important in industry, such as in the control of smelters where the carbon monoxide/carbon dioxide ratio indicates furnace efficiency. The new detector is based on cavity ring-down spectroscopy, in which laser light is reflected back and forth many times in a compact gas-filled optical cavity. The laser light may travel tens of kilometers before it escapes from the cavity. In this way, the laser light is able to interact efficiently with a gas sample, leading to very high detector sensitivity. Although cavity ring-down detectors have been around for several years, the new system is constructed of readily available photonics and fiber-optical components developed for the telecommunications industry, potentially making the highly sensitive detectors compact and cost-effective for a wide variety of medical and industrial applications. (Florian Englich, Paper CTuE5, Multi-wavelength sensing of CO and CO2 in air by rapidly-swept, continuous-wave cavity ringdown spectroscopy, Tuesday, June 3, 9:15 AM)

BUILDING A BETTER GENE SENSOR
An improved, chip-based sensor that can detect specified sequences in genetic material has been developed by researchers at Aachen University in Germany. The device will help identify genetic markers for inherited traits and diseases. It will also aid forensic scientists who must scan large samples for specific genetic material - the biological equivalent to finding a genetic needle in a DNA haystack. The gene chip is highly sensitive and simpler than previous gene sensors. The chip consists of a field of DNA probe strands anchored to a substrate. As samples of genetic material suspended in a fluid are washed past the probe strands, DNA materials that contain certain sequences of interest bind to the probe strands. Because the probe strands have characteristic mechanical resonant frequencies in the terahertz range, and the frequencies change when DNA binds to the probe strands, researchers can measure the amount of captured material by monitoring changes to a terahertz frequency signal applied to chip. The technique is simpler than fluorescent-labeling methods, which require the additional step to add fluorescent markers to probe strands. In addition, fluorescent markers can distort probe strands, leading to decreased accuracy in comparison to the terahertz frequency detection method. Peter Haring Bolivar will discuss the new gene chip in a talk on Monday, June 2 at 9:00 AM. (Paper CMB5, THz sensing of genes)

THE WORLD'S TINIEST SHOCKWAVES
By exploring laser-induced coulomb explosions, researchers at Johns Hopkins University and the State University of New York have predicted the smallest shockwaves ever. Coulomb explosions occur when a nano-corpuscle, a cluster of tens to thousands of atoms or molecules, is irradiated with a high intensity laser. The laser ionizes the nano-corpuscle and sweeps away the electrons, leaving behind the positively charged core which subsequently explodes due to the repulsive coulomb force of the positively charged particles in the cluster. The researchers found that if the cluster consists of a less dense layer covering a dense core, the explosion creates a shock wave followed by a slower-moving anti-shockwave. The two shockwaves form an expanding shock shell, which eventually encompasses the entire cluster of ions. The phenomenon may lead to unusual crystal-like formations at the shock wave surface and potentially even to nuclear reactions inside the shocked cluster. Alexander Kaplan will describe the shockwaves in paper CWN4, Shock-shells in coulomb explosion of nano-clusters, on Wednesday, June 4 at 5:30 PM.

FEMTOSECOND LASER PULSES MAY BRING LESS EXPENSIVE COLOR DISPLAYS
In what may eventually reduce the cost of high-quality color displays, researchers will present a new laser technique that shortens the manufacturing time of popular TFT (thin-film-transistor) displays. Such TFT screens are widely used in television displays, laptops, digital cameras and many other consumer electronics products. A superior material for making TFTs, especially in the case of large screens, is polysilicon, a solid consisting of many silicon crystals joined together. To produce a uniform, defect-free, high-performance polysilicon film, workers must first "anneal" silicon, or heat and then cool it in a highly controlled fashion. Annealing, in current practice, can be done with a furnace, which requires tens of hours, or it can be done with lasers, which takes a couple of minutes. In conventional laser annealing, a device known as an excimer laser requires heating the sample to 300-400 degrees C. Now, Alexei Zaitsev and his colleagues in the group of Prof. Ci-Ling Pan (National Chiao Tung University, Taiwan) have demonstrated a new kind of laser annealing that uses powerful bursts of light lasting only femtoseconds (quadrillionths of a second). Employing a femtosecond laser they only need to heat the sample up to 200 degrees C. In addition, the femtosecond laser fires at a more frequent rate than the excimer laser, promoting the creation of a more uniform annealed film. Moreover, the femtosecond approach uses near-infrared light, as opposed to the excimer laser's UV light, which results in undesirable heating and may degrade the substrate on which the polysilicon film is grown. Finally, the solid-state femtosecond laser technique avoids the handling of corrosive gases, which is required in the excimer approach. This talk will be the first presentation of successful results of low-temperature femtosecond laser annealing applied to TFT fabrication technology. (Paper CThM34, New low temperature femto-second laser annealing method for TFT fabrication technology; Thursday, June 5, 1:00 PM)

CLEO/QELS FEATURES
By combining a dynamic technical program of new, leading research with special forums emphasizing the topics on the forefront of the industry and an applications-oriented exhibition, CLEO/QELS provides a backdrop for in-depth analysis of the advancements of the future and industry functions of today. The exhibit brings together prominent industry corporations to showcase their technologies and provide a snapshot of today's market. Programs such as the Lasers and Electro-Optics Applications Program (LEAP, http://www.cleoconference.org/leap.cfm) complement the exposition, highlighting many of the field's most relevant topics, including homeland defense, biomedical optics, emerging technologies, and business and management. Additionally, the career center provided at CLEO/QELS, enables employers, job seekers and colleagues to meet, discuss opportunities within the field and network.

ABOUT CLEO/QELS
With a distinguished history as one of the industry's leading events on laser science, the Conference on Lasers and Electro-Optics and the Quantum Electronics and Laser Science Conference (CLEO/QELS) is where laser technology was first introduced. CLEO/QELS combines the strength of peer-reviewed scientific programming with an applications-focused exhibition to showcase the present and future of this technology. Sponsored by the American Physical Society's (APS) Laser Science Division, the Institute of Electronic Engineers/Laser and Electro-Optics Society (IEEE/LEOS) and the Optical Society of America (OSA), CLEO/QELS provides an educational forum, complete with a dynamic Plenary, short courses, tutorials, workshops and more, on topics as diverse as its attendee base whose broad spectrum of interests range from biomedicine to defense to optical communications and beyond. For more information, visit the conference's Web site at www.cleoconference.org.