Influence of diffusion of excited particles on wavefront reversal in a gaseous medium

A theoretical investigation is made of the influence of diffusion of excited particles on the parameters of the process of wavefront reversal by a degenerate four-wave interaction in amplitude gratings formed in an inverted carbon dioxide gas. It is shown that the thermal motion of molecules makes the reversal efficiency and the optimal degree of saturation of the gain depend strongly on the direction of propagation of the reversed wave.