Content-addressable data storage by use of volume holograms

Data stored as volume holograms—optical interference patterns imprinted into a photosensitive storage material—can be accessed both by address and by content. An optical correlation-based search compares each input query against all stored records simultaneously, a massively parallel but inherently noisy analog process. With data encoding and signal postprocessing we demonstrate a holographic content-addressable data-storage system that searches digital data with high search fidelity. © 1999 Optical Society of America.