The diffraction phenomenon in consecutive parametric processes

The manifestation of diffraction effects in two coupled three-frequency collinear processes in the presence of a single intense pump wave in a nonlinear optical crystal with a regular domain structure is considered. A set of three coupled parabolic equations is solved by the Fourier transform method. Attention is focused on the analysis of the functions of image conversion from a signal frequency to a new frequency and to the image gain. It was established that the influence of the subsequent process of image conversion by means of frequency mixing weakly affects the initial process of nondegenerate parametric interaction.