Holographic associative memory and optical logic using 4W mixing in a liquid crystal light valve
E. I. Galavanova, Igor N. Kompanets, G. A. Lunyakova, Anatoly A. Vasiliev · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1993
A holographic associative memory in a feedforward network is implemented using photosensitive liquid crystal light valve (LCLV) as a phase conjugate mirror (PCM). In the case of three simple binary images stored in the Fourier hologram the completely reconstructed single output image (rectangle) is observed with only a quarter of the image present as an input. Because of non-zero cross correlation and high gain the restoration remains even if the input image is rotated by 25 degree(s) about the optical axis and is either tilted or swung horizontally by up to 45 degree(s). Parallel analog and digital optical computing operations are demonstrated by using an interferometric arrangement with a LCLV-based PCM. Image subtraction, coherent and incoherent image addition, OR, XOR, and NOT optical gates are achieved by controlling the phase difference between two spatially multiplexed signal-bearing waves.