Photorefractive grating formulation with any light modulation and excitation: exact and approximate steady-state analytic solutions

A hologram generally is formed in a photorefractive crystal by the interact ion of the grating formulation that is due to the space-charge field that g rows from the beam interference pattern and of the beam energy exchange tha t results from two-beam coupling in the grating. Analytic expressions for t he grating recording formed by this interaction can be obtained only by sim ultaneous solution of the material equations and the coupled-wave equations . Using Moharam's space-charge field function, we deduce both the exact ste ady-state analytic solution for two-beam coupling under any boundary-light modulation and constant-light excitation and the approximate analytic solut ions with distance-dependent light excitation. Based on Kukhtarev's idea of three-step calculation, the formulation of a hologram under any light modu lation and excitation is further solved analytically. These steady-state an alytic solutions understanding are useful in arriving at a clearer and more exact understanding of photorefractive two-beam coupling and holographic r ecording. (C) 2000 Optical Society of America [S0740-3224(00)01306-0].