Digital and analogue holographic associative memories

In this paper we consider digital and analogue implementations of optical associative memories. Both techniques rely on the holographic manipulation of optical information. In the digital scheme, which is based on an optical version of the Hopfield model, computer-generated holograms achieve this, whilst for the analogue processor, Fourier transform holograms are used. We discuss how these primitive associative memory systems could be extended to incorporate the learning algorithms required by the more flexible, and useful, neural network architectures.