Abstract

Photorefractive crystals have been widely studied in recent years. The dynamic holographic nature, high-resolution, and energy coupling effect of photorefractive crystals make them especially useful in optical image processing, optical computing and optical interconnections [1]. Real-time optical image correlators have been demonstrated experimentally in a variety of photorefractive crystals [2, 3]. However, due to the angular selectivity of Bragg diffraction in volume gratings, shift invariance in these correlators is hardly achieved. In this paper, we present experimental studies of a thin photorefractive Fe-LiNbO3 crystal plate and report the first observation of planar gratings in the samples. Such planar gratings are useful in achieving shift-invariant real-time optical image correlators.

© 1992 Optical Society of America