Multilayer Volume Holographic Optical Memory

reference-wave hologram. The proposed recording method permits more-eff icient use of the recording medium and yields greater storage density than spherical or plane-wave reference beams. Experimental results of multiple hologram storage and replay in a photorefractive crystal of iron-doped lithium niobate are presented. The mechanisms of lateral and longitudinal shift selectivity are described theoretically and shown to agree with experimental measurements. 1999 Optical Society of America OCIS codes: 210.0210, 090.0090, 210.2860, 030.6140, 090.4220. Holographic memory has been a subject of interest for decades since it was suggested by van Heerden. High information density, parallel access, and high-speed retrieval are among the features that make this technique of data storage so attractive. Selective properties of volume holograms that are due to angular 2,3 or wavelength 4 deviation from the Bragg condition as well as to reference-beam phase encoding 5,6 are metho