PHASE-MODULATED PARAMETRIC ANTI-STOKES STIMULATED RAMAN SCATTERING OF CHERENKOV-TYPE IN SELF-FOCUSING AREAS OF EXCITING RADIATION

The influence of the speed of the focal point under self-modulation of the phase and self-focusing on the frequency-angular radiation spectra of a parametric stimulated Raman scattering (SRS) antiStokes component is considered. The phase self-modulation of both exciting and scattered anti-Stokes radiation is taken into consideration. The creation of broadened anti-Stokes frequencyangular bands is explained. The most intense frequency-angular bands, which are described by relations typical of the Cherenkov radiation, are generated when the speed of the self-focused focal point coincides with the phase velocity of a nonlinear polarization at the anti-Stokes Raman frequency and the phase velocity of a scattered axial radiation. In particular, under the excitation by nanosecond laser pulses, such bands in toluene reach shifts of approximate to-200 cm(-1) relatively to the anti-Stokes Raman frequency.