Wavefront reversal accompanied by frequency conversion in sodium vapor

An investigation was made of the quality of reconstruction of the signal wavefront in a single-pass system for compensation of phase distortions accompanied by frequency up-conversion. It was found that the best resolution and contrast were achieved when the reconstructed field was observed in the optimal focusing plane and the image of an inhomogeneous medium was transferred to the center of a nonlinear converter. The efficiency of the parametric process was enhanced by two-photon excitation of the 3s–4s transition in sodium vapor. The converter resolution was 13 lines/mm. The dependence of the contrast in the reconstructed field on the parameters of the compensation system was determined.