A. Yu. Sebrant

Materials processing by high-repetition-rate pulsed excimer and carbon dioxide lasers

Recently created pulsed gas lasers with high pulse repetition rate produce radiation in the IR [ V. Yu. Baranov , in Molecular Gas Lasers. Physics Applications, VelikhovE. P., Ed. ( Mir, Moscow, 1981), pp. 252– 255] and the UV ( V. Yu. Baranov , in Proceedings, International Conference on Lasers, 14–18 Dec. 1981, pp. 968– 974) regions of the spectrum. These lasers are widely used in research on the selective excitation of matter. This field of study includes laser isotope separation { G. I. Abdushelashvili , Kvantovaya Elektron. (Moscow)9, 743 ( 1982) [ Sov. J. Quantum Electron.12, 459 ( 1982)]} and laser-induced chemical reactions [ V. Yu. Baranov , Preprint IAE 3693/13 ( Moscow, 1982)]. But there are few publications dealing with uses of high-repetition-rate lasers for materials processing, although this problem undoubtedly is of considerable scientific interest.

Interaction of laser ablation plasma plume with grid screens

Optical emission spectroscopy and charge collector time‐of‐flight measurements have been used to study interaction of laser ablation carbon plasma with grid screens in vacuum under conditions typical for pulsed laser deposition of thin diamondlike films. The effect of velocity distribution transformation of the ion flow has been observed and studied in a variety of experimental conditions. Our results indicate that the observed phenomenon is due to interaction of two plasma flows, the initial expanding one and the fraction of that flow scattered by the substrate or the screen. Three typical modes of velocity distribution function transformation have been observed depending on the plasma density: linear attenuation of the flow density, nonlinear attenuation of the slow ‘‘tail’’ of the velocity distribution function, and nonlinear transformation of the entire velocity spectrum. The latter regime occurs when plasma is throttling through the fine mesh screen. Our observations show that the reported phenomenon...

Resonant phenomena in laser excitation of surface waves on solids

Excitation of surface waves by a moving laser beam has been studied both theoretically and experimentally. Using periodic surface structures as an example, it is demonstrated that the type of excited wave and the rate of its growth depend resonantly on the beam velocity. Experimental data show that resonant excitation of different periodic surface structures can change the spatial distribution of the absorbed laser energy. >