Holographic data storage systems implemented with photorefractive materials

In this paper, we review the state-of-the-art in holographic data storage, with particular emphasis on the interplay between materials and systems issues. In a generic configuration, a reference and object beam are incident on a recording medium. Electronic digital bit streams are impressed onto a laser beam via a spatial light modulator (SLM) in the form of 2-D digital bit patterns or pages. Multiple pages are superimposed in a stack by angular, phase or wavelength encoding in the Fourier domain. The total recording volume is addressed by scanning both writing beams across the surface of the storage medium. Readout in each stack is achieved by capturing the reconstructed bit pattern on a CCD or other suitable detector array. The medium may consist of a monolithic single crystal or a mozaic of fibers ordered in a regular pattern