Numerical studies of externally pumped phase conjugation in photorefractive crystals with applied electric fields

In the configuration of four-wave mixing, the output intensity and output phase of the conjugate beam in a photorefractive BaTiO₃:Ce crystal are numerically studied. The fidelity of the conjugate beam is analyzed. When an external electric field is applied to the crystal, the intensity of the conjugate beam can be enhanced, but its phase is no longer exactly conjugate to the input phase. The phase conjugate fidelity is, therefore, reduced.