Perturbative analysis of photorefractive fundamental space-charge field with phase modulation at large modulation depths

We discuss the kinetics of the photorefractive fundamental space-charge fie ld with phase-modulation at large modulation depth of the interference patt ern. When no external field is applied, the influence of large modulation d epth on the corrected fundamental space-charge field must be considered at low phase-modulation frequency and at small diffusion field. For the drifte d case, the corrected fundamental space-charge field will be changed for va rious external applied fields at low phase-modulation frequency. As two-wav e coupling is not neglected, the corrected fundamental space-charge field w ill not be in agreement with the case of no two-wave coupling. (C) 1999 Pub lished by Elsevier Science B.V. All rights reserved.