Investigation of stimulated Mandelstam - Brillouin scattering during beams passage in the limited space of gas medium

摘要

Induced beam scattering at small angles in the acoustic reso¬nator has been experimentally discovered and theoretically explai¬ned. For a single-mode, excitation scattering angle as well as the acoustic vibration frequency are proportiomal to the emission in¬tensity and the area of the longitudional section of resonator The higher beam divergence is the higher is the initial field and acoustic vibrations intensity in the resonator. For rather high longitudional dimensions of the acoustic resonators a theory has been summarized in case of multy-mode excitation of acoustic waves during Mandelstam-Brillouin stimulated scattering (MBSS). If it happens an angular spectrum of scattered waves must be excited which is located near angle Bregg corresponding to the lowest space frequency of acoustic vibrations. In case of considerable energy pumping into the scattering light, Bregg peak of angular distribution will be close to the half-divergence angle of pumping or priming.