Effects of photo-quenching-buildup and saturation of the induced impurity grating in ZnSe:Cr crystals

A model is proposed and calculations are performed to elucidate the effects of anomalous kinetics and dynamics of transient light self-diffraction signals (“a dip and a buildup” upon the termination of the grating generation pulse and saturation effects) observed in experiments on four-wave mixing in crystals doped with deep impurities. These observations are explained by the effects of optical depletion of local sites by the same grating generation pulse with only the subsequent buildup of the impurity grating through the capture of band carriers by these sites to form the previously created light-dynamic grating.