Lawrence Normie in Israel
JERUSALEM -- A glimpse into the future by the laser's discoverer and a retrospective on the development of holography highlighted the 10th Meeting on Optical Engineering held last month at Jerusalem's International Convention Center. Keynote speakers at the meeting, which marked the 16th anniversary of Israel's optics industry, were Arthur L. Schawlow of Stanford University and Emmet N. Leith of the University of Michigan.
Schawlow's look at the future focused on lasers' increasing use in atomic cooling to temperatures below 1 µK, where atoms exhibit optical-like interference phenomena, but differ from light in that they can be placed into quantum superposed states in two hyperfine energy levels. Schawlow explained that because of photon recoil, an atom in each of these levels has a different velocity and can travel along alternative paths and then be made to recombine and interfere.
Extremely sharp resonances observed in this way are being to used to measure the acceleration of gravity with unprecedented precision. Such atomic interference can also be used to construct extremely sensitive gyroscopes.
A puzzling problem
Schawlow also raised the puzzling issue of the nonlocality of quantum coupling between atoms or photons that are produced in superposed states and then separated. Coupling, he noted, has been demonstrated to persist until measurements are made on these atoms, even if they are propagating in opposite directions. Schawlow questioned whether this effect extends to very large separations and if the correlation is truly instantaneous.
Leith chronicled the development of holography, which began in 1947 as a scientific curiosity and now finds widespread industrial uses such as image correction and nondestructive testing. Leith pointed out that while it is possible to fabricate holograms with lasers for ordinary light viewing, he is doubtful that scientists can soon develop a technique for producing holograms with ordinary light.
Also speaking at the special session was C.T. Elliot of the UK's Defense Research Agency (DRA), who reported on DRA's advances in the development of noncryogenically cooled IR devices based on narrow-gap semiconductor devices such as InSb and MCT. He predicted that noncooled IR devices such as night sight goggles will soon be available at a cost low enough to equip every soldier. Elliot also revealed details on DRA's work in the fabrication of "negative luminescence" devices, in which the normal equilibrium background radiation is "switched off" to make them appear cold.
Elliot's presentation included startling video footage of negative luminescence devices in operation. Both positive and negative luminescence LED sources along with uncooled detectors are finding applications in toxic gas sensing, environmental monitoring and spectroscopy. Other potential applications include IR flux references to perform nonuniformity correction in staring IR images, DC restoration in scanned-imagers, detector cold shields, dynamic infrared scene simulators and miniature spectrometers.
Many countries represented
Several hundred participants from the US, UK, Israel, Germany, Switzerland, Italy, Spain, Portugal, Russia, China, Japan and India attended the three-day event sponsored by SPIE, the International Commission for Optics, the European Optical Society and the Asia-Pacific Optics Federation. Approximately 250 papers covered solid-state lasers, diffractive and nonlinear optics, applications in medicine and biology, fiber optics, optical communications, as well as new materials and components. Sessions on atmospheric optics and remote sensing figured prominently.
The meeting was marked by a retrospective exhibition featuring highlights of major past achievements as well as new developments by Israeli universities and photonics firms.