HOLOGRAPHIC RECORDING IN PHOTOREFRACTIVE THIN-FILMS - EDGE EFFECTS

The initial holographic recording rate has been analytically studied for a photorefractive thin slab. The finite thickness is explicitly taken into account by using a two-dimensional formulation (coordinates x and z parallel and perpendicular to the slab faces, respectively). It is shown that for a thickness comparable to the grating period, the solution appreciably departs from the usual one-dimensional result, i.e., edge effects are remarkable. In particular, significant space-charge fields perpendicular to the slab faces are generated. These effects may substantially modify the diffraction properties of the recorded photorefractive gratings, as exemplified for a GaAs film. (C) 1995 American Institute of Physics.