Volume holographic recording and readout for 90-deg geometry

Abstract

When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type dif- fracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function ap- proach based on 2-D Laplace transforms. In a second series of investi- gations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various de- pendences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the intensity (as in the case of Kerr-type media or photorefractives with predominantly photovol- taic effect) and to the derivative of the intensity (as in diffusion-dominated photorefractives) are considered. Two-dimensional nonlinear coupled equations are developed for the two (Bragg) orders for both cases. Closed form solutions are obtained for the first case, indicating only non- linearly induced self and cross-phase coupling. A simple experiment in- volving simultaneous recording and readout using photorefractive lithium niobate crystal indicates beam profile distortion, which may be expected in such 90-deg geometries. © 2004 Society of Photo-Optical Instrumentation Engi- neers. (DOI: 10.1117/1.1774195)