Description of readout processes during strong beam coupling

Abstract

We show, using the symmetry properties of the coupled-wave equations for the transmission and reflection geometries, that any readout characteristic of dynamic spatially nonuniform index gratings in photorefractive crystals can be explicitly expressed through the characteristics of the recording light beams. This approach is applied to describe the impact of beam coupling on the diffraction efficiency of dynamic gratings and on the output intensities of the light beams at instantaneous input phase changes (light grating translation). Further implications of this general approach are discussed.

Feedback-Controlled Photorefractive Beam Coupling

“…Broadly speaking, the method used allows to express any readout characteristic of the dynamic grating through the input and output recording amplitudes regardless of the type of PR response. Particular applications of this method can be found in [44].…”

“…They allow us to express h explicitly through the recording amplitudes [44]. Furthermore, we have jf…”

“…These includes the output intensities and phases of the S-and R-beams in steady state (with R, S, E K being time constants or in the presence of a frequency shift V when RS Ã , E K / exp (iVt)) ) and the diffraction efficiency of the recorded dynamic grating [1,2,43,44]. The Kogelnik relations (6.4) are applicable only in the limit of weak coupling when jF jd ( 1 and h ( 1.…”