Conversion of λ = 308 nm radiation at pulse repetition frequencies up to 600 Hz by stimulated Raman scattering in compressed hydrogen

An experimental investigation was made of stimulated Raman scattering, in compressed hydrogen, of radiation from an electric-discharge wide-band pulse-periodic electron-beam controlled XeCl laser with a divergence of 10^– 4–10^– 5 rad, an energy per pulse up to 0.5 J, and a pulse repetition frequency f up to 600 Hz. Under specified experimental conditions the energy efficiency of conversion to the first (353 nm), second (414 nm), and third (499 nm) Stokes components was 45, 40, and 28%, respectively. The efficiency of stimulated Raman scattering conversion decreased in the pulse-periodic regime on increase in f, so that at f = 500 Hz and 20 Hz the efficiency of conversion to the second and third Stokes components was 50% of the corresponding values for single pulses. A theoretical interpretation of the results obtained was developed. The main reason for the observed behavior was a reduction in the gains of the higher Stokes components because of heating of the scattering medium.