Optical constants for thin films of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, Os, Pt, and Au from 24 A to 1216 A.

Reflectance vs incidence angle measurements have been performed from 24 A to 1216 A on electron-beam evaporated samples of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, and Au, and using a nonlinear least-squares curve-fitting technique, the optical constants have been determined. Independently measured values of the incident beam polarization, film thicknesses, and film surface roughnesses are incorporated into the derivation of the optical constants. Additionally, Auger electron spectroscopy depth profiling measurements have been performed on each sample to characterize sample composition including oxidation and contamination.

Optical constants for thin films of C, diamond, Al, Si, and CVD SIC from 24 A to 1216 A.

A method for deriving optical constants from reflectance vs angle of incidence measurements using a nonlinear least-squares curve-fitting technique based on the chi(2) test of fit is presented and used to derive optical constants for several thin-film materials. The curve-fitting technique incorporates independently measured values for the film surface roughness, film thickness, and incident beam polarization. The technique also provides a direct method for estimating probable errors in the derived optical constants. Data are presented from 24 A to 1216 A for thin-film samples of C, synthetic diamond, Al, Si, and CVD SiC. Auger electron spectroscopy depth profiling measurements were performed on some of the samples to characterize sample composition including oxidation and contamination.

Extreme ultraviolet reflectance degradation of aluminum and silicon from surface oxidation.

We have performed in situ oxide contamination and XUV reflectance vs angle of incidence studies on fresh aluminum and silicon films evaporated in an ultrahigh vacuum system (base pressure 2 x 10(-10)Torr). Our ellipsometric measurements indicate that a surface monolayer of oxide forms on aluminum (1 h at 2 x10(-8) Torr oxygen) and silicon (1 h at 10-(7) -Torr oxygen). The monolayer formation time is inversely proportional to oxygen pressure. Our reflectance vs angle of incidence measurements at 58.4-nm wavelength indicate that unoxidized aluminum and silicon coatings can be used as multifacet retroreflectors with net retroreflectances in excess of 75% for aluminum and 50% for silicon.

Laser-induced damage in optical materials: sixteenth ASTM symposium.

The Sixteenth Annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, CO, 15-17 Oct. 1984. The Symposium was held under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Project Agency, the Department of Energy, the Office of Naval Research, and the Air Force Office of Scientific Research. Approximately 180 scientists attended the Symposium, including representatives from England, France, The Netherlands, Scotland, and West Germany. The Symposium was divided into sessions concerning Materials and Measurements, Mirrors and Surfaces, Thin Films, and Fundamental Mechanisms. As in previous years, the emphasis of the papers presented at the Symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high-power apparatus. The wavelength range of prime interest was from 10.6,microm to the UV region. Highlights included surface characterization, thin-film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. Harold E. Bennett of the U.S. Naval Weapons Center, Arthur H. Guenther of the U.S. Air Force Weapons Laboratory, David Milam of the Lawrence Livermore National Laboratory, and Brian E. Newnam of the Los Alamos National Laboratory were cochairmen of the Symposium.

Laser induced damage in optical materials: twelfth ASTM symposium.

The twelfth annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 30 Sept.-l Oct., 1980. The symposium was held under the auspices of ASTM Committee F-l, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Projects Agency, the Department of Energy, the Office of Naval Research, and the Air Force Office of Scientific research. Over 150 scientists attended the symposium, including representatives of the United Kingdom, France, Japan, and West Germany. The symposium was divided into sessions concerning materials and measurements, mirrors and surfaces, thin films, and finally fundamental mechanisms. As in previous years, the emphasis of the papers presented at the symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high power systems. The wavelength range of prime interest was from 10.6 microm to the UV region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength was discussed in detail. Harold E. Bennett of the Naval Weapons Center, Alexander J. Glass of the Lawrence Livermore National Laboratory, Arthur H. Guenther of the Air Force Weapons Laboratory, and Brian E. Newnam of the Los Alamos National Laboratory were cochairmen of the symposium. The thirteenth annual symposium is scheduled for 17-18 Nov. 1981 at the National Bureau of Standards, Boulder, Colorado.

Laser induced damage in optical materials: eleventh ASTM symposium.

The eleventh Symposium on Optical Materials for High-Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 30-31 October 1979. The symposium was held under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Projects Agency, the Department of Energy, and the Office of Naval Research. About 150 scientists attended the symposium, including representatives of the United Kingdom, France, Canada, Japan, West Germany, and Denmark. The symposium was divided into sessions concerning transparent optical materials and the measurement of their properties, mirrors and surfaces, thin film characteristics, thin film damage, considerations for high-power systems, and finally theory and breakdown. As in previous years, the emphasis of the papers presented at the symposium was directed toward new frontiers and new developments. Particular emphasis was given to materials for high-power apparatus. The wavelength range of prime interest was from 10.6 microm to the UV region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength was discussed in detail. Harold E. Bennett of the Naval Weapons Center, Alexander J. Glass of the Lawrence Livermore Laboratory, Arthur H. Guenther of the Air Force Weapons Laboratory, and Brian E. Newnam of the Los Alamos Scientific Laboratory were cochairpersons. The twelfth annual symposium is scheduled for 30 September-1 October 1980 at the National Bureau of Standards, Boulder, Colorado.

Ocular hazard from picosecond pulses of Nd: YAG laser radiation.

Seven rhesus monkeys (14 eyes) were exposed to 1064-nanometer radiation in single pulses of 25 to 35 picoseconds fromn a mode-locked Nd: YA G laser. Threshold injury resulted from single pulses with a mnean energy of 13 +/- 3 mnicrojoules. Electron microscopy of the retina revealed that damnage was highly localized in the photoreceptor and pigmented epithelial cells at the oluter retina. Membrane disruption, distorted outer segmtzents, and abnormnal melanin granules resembling fetal premelanosomnies were observed.