Patent ID: 6178019
Filing Date: 2001-01-23
Classification: G11B,G11C

Abstract:
A system for controlling selectivity in a holographic memory system (HMS) for location and retrieval of holographically stored data, said system comprising:a holographic memory cell (HMC) having holographic data stored therein;a holographic optical element (HOE) having stored therein a hologram of a HMS reference beam having a predetermined bandwidth;a plane wave source for generating a plane wave signal and for directing said plane wave signal toward said HOE; anda filter, located between said plane wave source and said HOE for filtering said plane wave signal, wherein, upon illumination of said HOE by said filtered plane wave signal, said HOE projects toward said HMC a modified HMS reference beam having a bandwidth modified from said predetermined HMS reference beam bandwidth and being reconstructed from said filtered plane wave signal and said hologram of said HMS reference beam;said modified HMS reference beam including low spatial frequency components of the HMS reference beam to provide a reduced scan resolution for locating a desired holographic data previously stored in said HMC using the HMS reference beam.