Numerical investigation of the influence of the strictive self-interaction on the quality of phase conjugation in the course of stimulated Brillouin scattering

The influence of the strictive self-interaction on the threshold and quality of phase conjugation in the course of stimulated Brillouin scattering (SBS) was investigated numerically in the linear approximation for steady-state linearly polarised pumping. The calculations were carried out for the three-dimensional case of a Gaussian pump beam and a beam representing a superposition of 10 x 10 Hermitian-Gaussian modes with random phases. It was found that in the case of a Gaussian beam the growth of the strictive aberrations leads to a significant reduction of the SBS threshold but has little influence on the conjugation quality. In the case of a pump beam with a divergence exceeding the diffraction limit such growth Of the strictive aberrations results (on the average) in lowering the SBS threshold and in deterioration of the conjugation quality. The calculated results depend strongly on the specific phase combination of the superposed modes.