Wavefront reversal of optical radiation using feedback in four-wave interaction

A theoretical analysis is made of wavefront reversal which is not sensitive to the optical quality of the nonlinear wavefront-reversing medium when complex-conjugate reference waves are formed spontaneously. An investigation is made of the linear and nonlinear stages of reversed wave generation in various nonlinear media using feedback in degenerate and nondegenerate four-wave interaction. It is shown that in nonamplifying nonlinear media this method can only be achieved by additional amplification of the radiation reflected from the nonlinear medium.