Compensation for phase distortions by three-frequency parametric interaction

An analysis is made of the compensation for phase distortions by wavefront reversal using a parametric frequency converter or a linear spatial filter. Estimates are made of the required accuracy for the transfer of the optimal focusing plane, and of the permissible nonmonochromaticity and divergence of the pump radiation in regular and random models of an inhomogeneous medium. It is shown that the limiting transverse inhomogeneity scale is governed by the width of the converter spread function and the maximum phase lead may be of the order of 2π. The results of the calculations were verified experimentally for generation of difference-frequency radiation in a quadratically nonlinear medium.