NEWS BRIEFS: A PREVIEW OF NEW RESEARCH
The following news briefs describe some of the most innovative technical highlights to be presented at the meeting. For the full abstracts of any of these papers or for more information on the conference's program, visit the meeting's website at www.frontiersinoptics.org or contact Colleen Morrison, email@example.com.
OSA/LS Joint Plenary Session features three world-renowned keynote speakers:
- Presidential Science Advisor John Marburger
- Roger Angel from the University of Arizona, "Ground and space telescopes to observe extra-solar planets"
- Gerald Gabrielse from Harvard University, "Observation of cold antihydrogen"
Eric Mazur (firstname.lastname@example.org, http://mazur-www.
Optical Telescopes Could Detect Life Beyond Solar System
Wesley Traub of the Harvard Smithsonian Center for Astrophysics (email@example.com) will discuss telescope designs that could potentially detect signs of life on planets beyond our solar system. Examining up to 150 nearby stars, these new telescopes would obtain highly detailed optical images in the visible part of the light spectrum. Besides having the ability to detect new planets, such high-resolution visible images could indicate planetary oxygen, water, ozone, air, and possibly even land plants (by recording the distinctive light that would be reflected by chlorophyll). To capture these features, scientists on NASA's Terrestrial Finder Program propose the design of a state-of-the-art "coronagraph," a telescope that blocks out the central light from a star to detect much fainter surrounding objects. In order to detect such features on an Earth-like planet in a nearby star, the coronagraph must have an extremely large mirror (about eight meters in diameter) with extremely smooth surfaces so that there cannot be any bumps larger than a size of a hydrogen atom (or about 1/10,000 of a wavelength of visible light). "This will be far, far better a telescope than has ever been built," Traub says, "and today there are teams of people working to make such a telescope and to send it to space sometime in the coming decade." (Paper ThW3, Thursday, 11 AM)
Improvements in Face Recognition Technology
Secure access to physical and virtual spaces is becoming increasingly important for security. Passwords and PINs can be lost or forgotten. However, using biometrics (for instance a face, fingerprint or iris) for matching a live subject to a stored template, security can be improved. At Carnegie Mellon University, Vijayakumar Bhagavatula (firstname.lastname@example.org) and his team have been developing methods to achieve improved biometric verification using a tool called "correlation filters." This approach provides several advantages such as graceful degradation (part of the face can be occluded and it is still recognized), shift-invariance (images do not have to be centered) and smaller error rates. Bhagavatula will show results in which a filter trained on just three views of a person's face could successfully recognize 21 different views of that person's face and reject faces of more than 60 others in that database. The same methods were also applied for fingerprint recognition and iris recognition and those results will also be shared. (Paper WOO4, Wednesday, 5:15 PM)
Making Holograms with Digital Cameras
Combining digital photography with computer number-crunching, a research group headed by Joseph Rosen from Ben-Gurion University in Israel (email@example.com) has developed a promising new method of recording holograms of any three-dimensional scene. In addition to making it easier for industry to produce holograms, the new method can potentially give consumers the ability to make 3-D movies of events, by using digital cameras and special computer software. Conventional holographic recording requires lasers and complicated optical systems. In contrast, Rosen and his students, David Abookasis and Youzhi Li, use a standard digital camera to take a set of many pictures of the 3-D object from different points of view. The set of pictures is sent to a computer, and mathematically processed with a new algorithm developed by the researchers. The computer output is a hologram, which can be printed out on a hardcopy transparency or on a screen such as an LCD (liquid crystal display). When this hologram is properly illuminated, a real 3-D image of the original object is reconstructed in front of the viewer's eyes. It is important to note that this hologram is not related to other non-laser holograms, such as multiplex or stereoscopic holograms, which work by supplying two different images, one for each eye. Rosen says these types do not mimic the 3-D scene completely -- for example, they cannot capture all the ways in which objects in the hologram can come into focus at different distances and angles from the observer. According to Rosen, their hologram is the only non-laser technique that recovers all the 3-D effects of the original scene. (Paper ThV2, Thursday, 10:45 AM)
Entangled Photons for Long-Distance Calibration
Testing optical devices such as telescopes and spectrometers often requires a carefully calibrated source of photons, which are then sent to an optical device to see how it responds. But when the optical device is located in certain, hard to reach places such as aboard the International Space Station, it's not always easy or cost-effective to carry a calibrated source to the optical instrument. Researchers at the University of Maryland, Baltimore County, have developed a scheme involving quantum mechanically entangled photons to accurately test optical equipment at remote locations. Giuliano Scarcelli (firstname.lastname@example.org) and coworkers have built a prototype of a system that allows them to precisely characterize optical devices at a distance by taking advantage of the fact that entangled photons have very special relationships. If the state of one of a pair of entangled photons is measured, the state of the other photon can be unequivocally calculated from quantum mechanical rules. In order to take advantage of this relationship, the researchers first create a pair of entangled photons. One photon is sent to a monochromator, where its characteristics are precisely recorded. The second photon is sent to the device to be tested, and the device's response to the single photon signal is recorded and sent back to the lab. Because the researchers know the state of the second photon by looking at the first, they can determine the response of the remote optical device to a well-known signal. As a result, they know how to interpret the remote device's measurements. So far, the researchers have experimentally confirmed their results on instruments located a not-so-remote two meters from the entangled photon source, but the tests show that longer distance tests are feasible in principle. (Paper WF4, Wednesday, 9:00 AM)
Editor's Note: Images and full and lay-language papers of selected talks available upon request.
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Frontiers in Optics 2003
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