Theory of Stimulated Brillouin and Raman Scattering

Stimulated Raman and Brillouin scattering can be described as the interaction of several light waves with optical and acoustic-phonon waves, respectively. The coupling parameters can be derived both classically and quantum mechanically. A prototype solution is given for the coupling of infinite plane Stokes and anti-Stokes waves satisfying appropriate boundary conditions on a plane-parallel Raman cell, in which the laser intensity is assumed a constant parameter. Saturation effects, generation of higher order Raman radiation, and the effect of mode structure in the laser beam are treated in a more approximate and qualitative fashion. The theory can explain at least qualitatively most of the experimental findings, including the directional properties of the Raman radiation. Ideal experiments for clarifying the mechanism of the Raman effect are suggested.