Abstract

Multiplexing a large number of gratings in a volume holographic medium so that all images stored can be addressed independently is important for a wide range of applications such as high capacity data storage, optical interconnections, neural networks, and optical correlation. Large capacity memories have already been implemented using photorefractive crystals^1,2. However, in such dynamic materials, the image retrieval produces partial erasing of the memory. Fixing techniques are not adequate here as they generally hinder further updating of the memory. To overcome this problem, a new architecture was recently proposed which uses two holographic media^3,4. We here propose and demonstrate a flexible readoutrefreshing scheme that permits operating a dynamic memory for days without loss of information and using one holographic medium only, here a single photorefractive crystal.

© 1992 Optical Society of America