RAMAN PARAMETRIC LASERS EMITTING RADIATIO N WITH DISCRETE SPECTRUM AND BANDWIDTH EQUAL TO PUMP FREQUENCY

Analytical and numerical calculations show that the maximal spectral w idth of the region occupied by stimulated Raman scattering components whose intensities are of the same order of magnitude, is equal to the pump frequency. The conditions for attaining such a regime have been f ound. Rotational stimulated Raman scattering of focused biharmonic rad iation in hydrogen yields eight anti-Stokes and five Stokes components with relative intensities of 0.001 and 0.01 respectively. The dcghfdf ivergence of the components is approximately 1.5-2.5 diffraction limit s, width of individual lines deltanu less-than-or-equal-to 0.02 1/cm a nd duration of the Stokes components is much less than that of the ant i-Stokes components. It is qualitatively shown that the substantial di fference in the number of the components given by the plane wave theor y and obtained in the experiments is caused by the wave mismatch due t o diffraction.