SPATIAL DIFFERENTIATION OF OPTICAL-IMAGES USING SELECTIVE ERASURE OF PHOTOREFRACTIVE HOLOGRAMS

We propose and demonstrate a novel technique of spatial differentiatio n of optical images based on the selective erasure of holograms in pho torefractive crystals using a composite filter which consists of an am plitude and a phase filter. The net tilter is realized by controlling the modulation depth, amplitude of a. photorefractive grating using a one-dimensional Gaussian erasing beam in conjunction with a phase filt er in the reading beam's path, Experimental results are presented and compared with other type of filter.