Two-dimensional shifting tolerance of a volume-holographic correlator

A simple method for simulating two-dimensional (2-D) distributions of the d iffraction lights of a volume-holographic-type VanderLugt correlator is pro posed and demonstrated. The simulation results are similar to those of the corresponding experiments, and only a few dozen points are sampled from bot h the input and the reading patterns. We show that the shifting tolerance t o the reading pattern is a result of Bragg degeneracy and is not isotropic. The Bragg degeneracy generates different degrees of cross talk: between th e horizontal and the vertical directions. With the method we further simula te the 2-D shifting tolerance of the volume-holographic correlator. The sim ulation results offer a clear picture of the diffraction in a transmission volume hologram used as an optical spatial correlator. (C) 1999 Optical Soc iety of America. OCIS codes: 090.7330, 070.4550, 190.5330.