V. D. Pis'mennyi

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 [nn V. Yu.n Baranovn n , in nMolecular Gas Lasers. Physics Applications, nVelikhovE. P., Ed. (nMir, nMoscow, n1981), pp. n252–n255] and the UV (nn V. Yu.n Baranovn n , in nProceedings, International Conference on Lasers, 14–18 Dec. 1981, pp. n968–n974) 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 {nn G. I.n Abdushelashvilin n , nKvantovaya Elektron. (Moscow)9, n743 (n1982) [nSov. J. Quantum Electron.12, n459 (n1982)]} and laser-induced chemical reactions [nn V. Yu.n Baranovn n , nPreprint IAE 3693/13 (nMoscow, n1982)]. 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.

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. >

Two-Frequency IR Laser System on the Basis of SHG in the Crystal TnGeP2 For Investigation of the Radation-Substance Interaction

Publisher Summary The effective frequency conversion of CO 2 laser radiation has a significant practical importance in science and techniques, in particular, in an atmospheric laser remote sensing measurements, isotope separation, and laser-induced fusion. Pulse CO 2 lasers have the advantage of other radiation sources that are as follows: high efficiency, large frequency tunability, wide range in energy and pulse duration, and high mean power in a repetition pulse mode. The second and the fourth harmonic generators of CO 2 laser radiation with a pulse duration ∼100 ns, which are built currently on the basis of CdGeAs2 and ZnGeP2 single crystals, have low efficiency. The last is determined by the pump laser intensity and the nonlinear crystal length. The conversion efficiency is sufficiently limited by the surface damage because of the noticeable radiation absorption on the fundamental and second harmonic frequencies. The threshold energy fluence is weakly depended on the pulse duration in the range 1–100 ns, therefore, the pump peak intensity and as a result, conversion efficiency can be increased with 1 ns laser pulses. This chapter discusses the second harmonic generation (SHG) of nanosecond CO 2 laser pulses in a ZnGeP2 nonlinear crystal.