Time Measurement of Local Photorefractive Response of a Medium Using the π Shift of an Interference Pattern

Abstract

A method for the measurement of the recording/erasing time of dynamic phase gratings that are recorded by phase-modulated beams in photorefractive medium with local response is presented. The method is based on the detection of the intensity modulation of output beams in the course of rerecording of the grating after a shift of the interference pattern by one-half of spatial period. It is demonstrated that a relatively high sensitivity of the method is due to the selective detection of signals at a high frequency and a high efficiency of energy exchange of the recording beams in comparison with the diffraction of the probe beam. The application of the method in dynamic holographic seismographs is discussed.