Quality of wavefront reversal of multifrequency radiation by four-wave interaction

It is shown experimentally that broadening of the frequency spectrum of waves participating in four-wave interaction in a system with exactly counterpropagating reference waves results in an angular spread of the reflected radiation and thus causes a deterioration in the wavefront reversal quality. The angular spread is proportional to the angle of convergence of the signal and the parallel pump wave and to the width of the emission spectrum.