NONLINEAR OPTICAL PHASE CONJUGATE EFFECT CAUSED BY F^-₂ COLOR CENTER IN LiF CRYSTALS

We report the experimental observation of nonlinear optical phase conjugate (NOPC) effect caused by the resonant saturable absorption of F^-₂ centers in LiF crystals. The experiment was performed by making use of degenerate four-wave mixing in the laser cavity. We also give the curve of the phase conjugate reflectivity versus the incident energy of the probe light.