Correction of shape distortions in laser beams apodized with circular serrated apertures.

Flat-top laser beams produced with apodizers comprising a circular serrated aperture and spatial filter are not optimal for propagation over long distances. Residual intensity fluctuations across the overall smooth profile at the apodizer exit significantly accelerate degradation of the beam at small Fresnel numbers. By solving the parabolic equation for uniform and Gaussian beams propagating through a serrated aperture apodizer, we show that a narrow opaque ring installed inside the serrated aperture can largely suppress unwanted diffraction effects and bring the output amplitude profile close to the flattened Gaussian function.

Towards high-optical-strength, fluorine-resistant coatings for intracavity KrF laser optics.

Intracavity optics of e-beam-pumped high-energy KrF lasers should survive in a hostile environment of simultaneous irradiation by intensive UV laser light, scattered electrons, bremsstrahlung X-ray radiation, and permanent etching by a fluorine-containing working gas mixture. The present paper is focused on the research and development of high-optical-strength and fluorine-resistant AR coatings capable of protecting the fused silica windows and HR rare mirrors of these lasers against fluorine attack. The most promising coatings deposited by e-beam evaporation were -based compositions, which have low water content, good resistance to fluorine, and demonstrated the highest damage thresholds for AR coatings 29.

Remote helicopter-borne detector for searching of methane leaks.

Measurements of the content of various molecular impurities in the ambient air using helicopter- and aircraft-borne systems represent an extremely urgent challenge. In this respect, of special interest are the devices that that provide leakage monitoring in gas lines in order to prevent emergencies. In the paper results of the tunable diode laser-based instrument development and testing are presented.

UF6 enrichment measurements using TDLS techniques.

The objective of this work was investigation of possibility of tunable diode laser spectroscopy (TDLS) technique application for gaseous uranium hexafluoride (UF6) isotope measurement. Spectra of uranium hexafluoride gas mixture were investigated using two different Fourier Transform Spectrometers Vector 22 and Bruker 66v. Observed spectral features were identified and model spectra of different gas mixture components were developed.