IMAGE MULTIPLEXING BY SPECKLE IN A BSO CRYSTAL

A technique of multiple image storage in a BSO crystal by using speckl e patterns is proposed. It is based on the modulation of 3-D speckle g rains which appears when the image of a coherently illuminated input i s formed onto the crystal by an optical system whose pupil consists of two identical holes. Each image is stored in a sequential way by chan ging the pupil between images. The intensity distribution of the speck le pattern imaged onto the BSO crystal leads to a space-charge field b y drift of photocarriers, resulting in a refractive index modulation, The volume nature of the registered speckles is analyzed. The encoded images are retrieved by illuminating the crystal with a collimated He- Ne laser beam and by properly filtering the Fourier plane. Experimenta l results are presented. (C) 1998 Elsevier Science B.V. All rights res erved.