Abstract

Starting from the differential equations of Kukhtarev et al.¹, which describe the response of photorefractive materials, we apply the perturbation method to linearize these equations. Assuming two beams (one much stronger than the other) in the recording process, we estimate the dynamics of the formation of the refraction-index grating. Thereafter, with one of the beams shut off, we recalculate the decay of the grating profile. Results indicate a ringing behavior during the buildup process with a nonzero steady state for the "perturbed" refraction index. The (temporal) frequency of the oscillations and the buildup time constant depend on the applied electrical bias and the spatial period of the induced grating, as well as the physical parameters of the materials and the strengths of the illuminating fields. The decay process is also marked by oscillations, with the frequency and the decay time constant once again dependent on the above parameters. On the basis of the above information, we calculate the time dynamics of the normalized diffraction efficiency by means of the coupled-wave theory.

© 1990 Optical Society of America