Quality of phase-conjugation in nondegenerate four-wave mixing

One more promising application of the four-wave mixing process is the correction of arbitrary phase aberrations in an optical beam. In such applications, the fidelity as well as the efficiency of the phase-conjugation process needs to be considered in practice. The process which has received the most extensive attention to date is degenerate four-wave mixing (DFWM). The nonlinear interaction in this case is known to result in a perfect phase-conjugate provided high-quality pump beams are available and competing effects such as local self-focusing (or defocusing) can be neglected.