CONFERENCE PREVIEW: CLEO/Europe showcases research and applications

The second biennial European Conference on Lasers and Electro-Optics and European Quantum Electronics Conference (CLEO/Europe-EQEC) opens Sept. 8, 1996, in Hamburg, Germany. With a total of 22 topical areas covering subjects ranging from semiconductor lasers and medical and biological applications to the physics of coherent light sources, the technical program promises something for everyone. Joint symposia address quantum information processing, nanofabrication and microstructures, and high-power lasers and their applications. A series of short courses, including workshops and tutorials, provides an opportunity for attendees to expand their knowledge of specific topics.

In addition to the core technical program, the conference plenary presentations include a talk entitled "Ultracold Atoms: New Approaches and New Perspectives," given by C. Cohen-Tannoudji of Ecole Normale Supérieure et Collège de France, also "Semi conductor Lasers: Recent Advances and Prospects," presented by K. J. Ebeling of the Universität Ulm in Germany. CLEO/Europe also celebrates the 80th birthday of A. M. Prokhorov, who shared the 1964 Nobel Prize in physics with N. G. Basov for work that led to the discovery of the laser. Prokhorov will deliver a talk entitled "Solid-State Lasers: History and Aspects." As with other CLEO meetings, the conference also hosts a display of lasers and electro-optics equipment.

Program cochair Colin Webb of the University of Oxford, England, says, "There are some real advances in OPOs [optical parametric oscillators], fiber lasers, diode lasers, and diode-pumped lasers." Webb notes that European work in solid-state lasers is particularly strong and "heralds a new era in compact solid-state lasers." Also commenting on the CLEO/Europe program, cochair Günter Huber of the Universität Hamburg says that European work is strong on the fundamental side. "The problem is getting fast transfer from basic science to applications. We think this conference will help this transformation."

Within the solid-state laser arena, diode pumping remains an active area of research. A group from Thomson-CSF (Orsay, France) describes high packing and power densities in diode arrays. The arrays are useful not only in material processing but also for pumping other devices. Other papers include reports from Laser Zentrum Hamburg and the Optische Institut Berlin describing Nd:YAG devices with output powers of several hundred watts at 1.06 µm and many tens of watts at the second-harmonic wavelength of 532 nm. The Universität Hamburg also reports on a green-emitting laser; operating in a CW mode, the 2-mm-long microchip device produces about 1.2 W of output with an efficiency of more than 20%.

Microchip lasers and micro-optics technology are the subject of an invited talk from LETI (Grenoble, France), while researchers from Politecnico de Milano in Italy will discuss diode-pumped erbium:ytterbium microlasers.

Notwithstanding the high profile of work related to solid-state devices, advances in gas and dye lasers are still occurring. A joint Bulgarian and Scottish group has boosted the output power of a relatively small copper-vapor laser using hydrogen bromide. And in Australia conventional copper-vapor laser output levels have been doubled by modifying the gas mixtures. According to Webb, the improved lasers will address markets similar to those addressed by Q-switched Nd:YAG lasers, such as material processing. Other reports include recent advances in high-power infrared lasers from DLR in Stuttgart, Germany, and a discussion of new applications from ETH in Zurich, Switzerland.

Novel technologies

Liquid-crystal active-matrix displays, laser projectors, and liquid-crystal projection are featured in a special CLEO/Europe symposium on novel display technology that includes contributions from Philips, Thomson, Schneider, and Daimler-Benz. An EQEC symposium discusses the latest work on Bose-Einstein condensation, which includes condensation in a gas of sodium atoms and macroscopic quantum phenomena in Bose-condensed atomic gases. And a symposium on gravitational-wave detection includes discussion of efforts to study radiation in the 10- to 104-Hz range, such as the LISA (laser interferometer in space) mission.

No laser conference in Europe would be complete without a discussion of recent developments in restoration and preservation of ancient artifacts. At Oxford, British researchers are using laser ablation as part of a procedure for dating rocks and minerals, while a group led by Costas Fotakis (University of Crete, Greece) is developing diagnostics to sto¥laser ablation of contaminants on paintings once the actual painting is exposed.