Usage of photorefractive crystals in holographic associative correlators

Abstract

Photorefractive material have certain prospects for usage in coherent-optical schemes of the optical signal processing. Their values in this aspect are non-linear resopnse to the intensity of signal and variety of temporal characteristics of record and erasure of images, including holographic ones. In this presentation, questions connected with usage of photorefractive crystals in the holographic correlator with the associative resopnse to fragments of recognized signal were investigated. Particularity of the correlator scheme consists in getting response in the manner of the signal under investigation itself. Due to it, the level of signal identification increases under its associative processing. Use of spatial modulator of signal wave front and photorefractive crystals in the scheme allows to vary a structure of angular spectrum of recorded images when writing the holograms. In certain limits, it gives a possibility to control sensitivity of image as to change of structure of fragments which restore a hologram, keeping stable associative response.