Patent ID: 7787165

Claim:
A holographic memory system comprising: (a) a photorefractive crystal configured to store multibit holograms; (b) a single laser diode configured to emit a collimated laser beam to both write multibit data to and read the multibit data from the photorefractive crystal; (c) a multilevel spatial light modulator to encode the multibit data on an input beam split from the collimated laser beam, wherein: (i) the multibit data is encoded into a pixel data set comprising multiple bits per pixel; (ii) the multilevel spatial light modulator encodes the pixel data set into a single pixel by modulating the input beam into light bundles having durations represented by each bit of the pixel data set; and (iii) the multilevel spatial light modulator provides multibit data input conversion resulting in a multilevel beam; (d) a first imaging relay lens pair positioned between the multilevel spatial light modulator and the photorefractive crystal to image a multibit spatial light modulator image on a plane behind the photorefractive crystal and (e) one or more mirrors configured to steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal to read or write the multi-bit data.