Viacheslav S. Bukreev

Pulse compression of KrF laser radiation by stimulated scattering

Pulse compression of KrF laser radiation by stimulated scattering.Sergey S.Alimpiev, Viacheslav S.Bukreev, Vladimir I.Kusakin, Sergey V.Ukhansky,Alexey Z.Obidin, Sergey K.Vartapetov, Igor A.VeselovskyGeneral Physics Inst., 1 17942 Moscow, Vavilov str. 38, USSRABSTRACTWaveform conjugation of narrowband KrF laser with linewidth 0.02 cm1 and divergence iO rad wasinvestigated. By means of Brillouin scattering in SF6 gas the 12 ns duration pump pulse was compressed up to 1.5ns with energy efficiency about 80% and the laser beam divergence retention. The waveform conjugation underthermal Raleigh scattering in hexane, heptane and hot water was also investigated. The maximum efficiency inhexane was about 10% and scattered pulse duration 2.5 ns. Waveform conjugation in a wide region of liquidsabsorption coefficients was also observed.One of the methods to decrease the laser pulse duration is the use of nonlinear optics techniques. Amongthe most prospective ones are techniques based on stimulated scattering processes. The main advantages of suchpulse compression techniques are high efficiency, low background level of amplified spontaneous emission andpossibility of waveform conjugation. A properly selected conditions of stimulated scattering in principle allow toproduce pulses much shorter than the damping mode time Td. The most widespread are the compressors basedon stimulated Brillouin and Raman scattering 1,2 Brillouincompressors possess high energy efficiency, smallfrequency shift, so the scattered radiation can be amplified in the next amplifiering stages. The minimal scatteredpulse duration can be decreased up to Ts=.O. 1 Td and for Brillouin scattering in gases this value is about somehundreds picoseconds3. Raman scattering allows to produce much shorter pulses, but because of the largefrequency shift, the further amplification Stokes pulse demands low-efficiency retransformation to antistokescomponent.In the simplest scheme of compressor laser radiation is focused in the cell with the scattering medium. Amatter of principal in this case is the choose of focusing geometry: amplification length L, beam waste length Zd

Long pulse XeCl laser

This article reports on a long pulse excimer laser with autopreionization. Laser pulses with energy of 140 mJ and duration of 180 ns were generated using a discharge circuit built on the basis of main and peaking capacitors driven by a thyratron. Pulse duration of 250 ns and single frequency generation were achieved.

Multipurpose two-wavelength surgical laser

Prototype of a commercial laser system, capable of performing various surgical operations, was developed and produced. The laser unit can emit, separately or simultaneously, radiation with wavelengths 1.06 and 2.1 (mu) at an average power up to 30 and 6.5 W correspondingly. The construction of an optical scheme and power supply gives wide flexibility of the laser output parameters. Possible medical applications of the 1 - 2 micron laser system are considered.

Excimer laser with sealed x-ray preionizer

Excimer Laser with Sealed X-ray PreionizerVladimir V. Atezhev, Sergey R. Belov, Viacheslav S. Bukreev, Sergey K. Vartapetov, Alexander N.Zhukov, Ilnur T. Ziganshin, Alexander M. Prokhorov, Alexey E. Soldatkin, Yuri D. SlepanovGeneral Physics Inst., 1 17942 Moscow, Vavilov str. 38, USSRABSTRACTIn this paper we present the description of X-ray preionized excimer laser. For this laser the specialsealed metal-ceramic X-ray areionizer with cold cathode was constructed. The cathode was made from acarbon felt and had 4x80 cm area. The discharge volume was 70x4x3 cm3 and on XeCl one provided theenergy up to 2 J in a pulse.In the same discharge chamber the different type of preionizers ( spark discharges, UV laser radiation)were investigated. It was shown that the output energy depends rather the electron density uniformity thanthe electron concentration.For the pulse energy of excimer laser increasing high uniformity discharge in large volume must beproduced. In this case the demands upon discharge volume preionization are very strict. The main parametersof preionizer are the initial electrons density, its uniformity and the preionizers action on the gas mixture lifetime.UV preionization by spark discharges produces high electron density ( —