Abstract

Holographic memory has attracted a lot of interests because of its high storage capacity and fast parallel access.¹ In volume holographic memories data is stored as interference patterns formed by coherent beams of light. The information is imprinted on the object beam. Multiple pages of data are superimposed within the same volume of a storage medium. These pages, stored as separate holograms, can be independently accessed by changing either the angle,² wavelength³,⁴ or phase code⁵,⁶ 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 the number of bits in each stored page, and M is the number of pages superimposed in the same volume. Assuming one 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 read-out rates can be achieved.

© 1996 Optical Society of America