NUMERICAL-ANALYSIS OF SRS CONVERSION OF TERAWATT FEMTOSECOND UV PULSES

Citation
Ms. Dzhidzhoev et al., NUMERICAL-ANALYSIS OF SRS CONVERSION OF TERAWATT FEMTOSECOND UV PULSES, Laser physics, 6(5), 1996, pp. 963-970
Citations number
22
Categorie Soggetti
Optics,"Physics, Applied
Journal title
ISSN journal
1054660X
Volume
6
Issue
5
Year of publication
1996
Pages
963 - 970
Database
ISI
SICI code
1054-660X(1996)6:5<963:NOSCOT>2.0.ZU;2-A
Abstract
The results of numerical modeling of nonstationary forward SRS of femt osecond pulses in molecular dispersive gases are presented. The calcul ations are carried out in one-dimensional two-wave approximation takin g into account self- and cross-action of the pulses. For the first tim e the dynamics of a Stokes pulse build-up and the transformation of it s spectrum and temporal shape during amplification are traced up to th e saturation regime in CH4, NH3, H-2, and SF6. The fundamental role of group velocity mismatch, which determines the velocity of a Stokes pu lse with respect to a pump pulse is revealed. It is shown that there e xists a range of parameters where pulse compression takes place under optimum amplification with drastic sharpening of the leading edge of t he pulse. The parameters of SRS converter based on an oscillator and a two-stage amplifier with beam summation at She second stage are calcu lated. The pumping high-power femtosecond excimer system produces two beams with an energy of 1 J each at the wavelength of 308 nm and pulse duration of 300 fs. The converter provides conversion efficiency up t o 60%, threefold compression of the pulse, prepulse suppression, and s harpening of the leading edge.