HOROGRAM MEMORY DEVICE

摘要

NON-DESTRUCTIVE READOUT SCHEME FOR HOLOGRAPHIC STORAGE SYSTEM of the Invention A non-destructive readout scheme suitable for use with a holographic storage system having data stored in three spatial dimensions and one frequency dimension is described. The readout scheme and the holographic storage system use a preferred storage material which undergoes a reversible photochromic reaction involving two inhomogeneously broadened absorption bands. Information is written into the storage system by exposing the material to a holographic interference pattern of light at a frequency within either one of the two absorption bands. The non-destructive readout scheme involves reconstructing the original information by sensing the change in the index of refraction at a frequency just outside of and near either one of the two absorption bands. The readout scheme also includes sensing refractive index changes near one or more narrow absorption lines within either absorption band.