Abstract

We have demonstrated an all-optical implementation of an associative memory. An associative memory is a device which when addressed by a partial, noisy or distorted version of the stored data generates the complete version most closely associated with that input. We use a hologram as a storage medium in an optical feedback configuration which incorporates two phase-conjugate mirrors (PCMs). Holograms were chosen as the recording medium because the information is stored globally and is well suited to parallel processing. In addition the hologram is capable of storing multiple images by the use of angular multiplexing of the reference beams during recording. We exploit this inherent associative property by addressing the hologram simultaneously by both the object beam as well as the conjugate reference beam. The phase conjugate mirrors are used to provide regenerative feedback, optical gain and thresholding.

© 1986 Optical Society of America