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We describe a page—formatted random—access holographic memory capable of storing up to 160,000 holograms.A segmented mirror array allows a 2—dimensional angle scanner to provide access to any of the stored holograms.High—speed random access can be achieved with a non—mechanical angle scanner. We demonstrate holographicstorage and high—speed retrieval using an acousto—optic deflector (AOD). 1 INTRODUCTION In volume holographic memories data is stored in the interference patterns formed by coherent beams of light. The information is imprinted on one of these beams (object beam). Multiple pages of data can be superimposedwithin the same volume of a storage medium. These pages, stored as separate holograms, can be independently accessed by changing either the angle,' wavelength2'3 or phase code4'5 of the reference (non—information—bearing) beam. The storage capacity C achievable with each of these methods can be written as C = NM, where N is thenumber of bits in each stored page, and M is the number of pages superimposed in the same volume. Assumingone bit per pixel, current spatial light modulator (SLM) technology can provide 105_106 bits per stored page.Because these pixels are recalled in parallel by a single reference beam, very high data rates can be achieved.We describe a holographic data storage system in which the data rate is limited only by the material dynamicrange. By using the 90° interaction geometry, we have enough distinct reference angles for storage of 10,000holograms at a single location. A segmented mirror array enables non—mechanical scanners to provide high— |
