Patent ID: 7999984
Filing Date: 2011-08-16
Classification: G03H,G11B

Abstract:
1. A method to encode information holographically, comprising the steps of: providing information and a holographic data storage system; generating a plurality of data images, wherein each data image comprises a portion of said information; holographically encoding each of said plurality of data images in a holographic data storage medium; generating a plurality of identifiers; associating a different one of said plurality of identifiers with a different one of said plurality of data images; forming a directory image reciting each of said plurality of identifiers; encoding said directory image in a non-holographic data storage medium; displaying said directory image on a spatial light modulator; generating a reference beam using a lasing device, wherein said reference beam comprises an original reference beam intensity; generating a carrier beam using said lasing device; directing said carrier beam onto said spatial light modulator to form a data beam comprising said directory image; interacting said reference beam and said carrier beam to form a directory hologram comprising said directory image; encoding said directory hologram in said holographic data storage medium; illuminating said encoded directory hologram with said reference beam to generate a reconstructed directory image; evaluating said encoded directory hologram by comparing said reconstructed directory image with an encoded directory image; establishing a threshold correlation factor; determining a measured correlation factor by comparing said reconstructed directory image with said encoded directory image; determining if said measured correlation factor is greater than said threshold correlation factor; operative if said measured correlation factor is greater than said threshold correlation factor, verifying said encoded directory hologram; illuminating said encoded directory hologram with said data beam to generate a reconstructed reference beam comprising a reconstructed reference beam intensity; evaluating said encoded directory hologram by comparing said original reference beam intensity with said reconstructed reference beam intensity; establishing a threshold intensity ratio; determining a measured intensity ratio by dividing said reconstructed reference beam intensity by said original reference beam intensity; determining if said measured intensity ratio is greater than said threshold intensity ratio; operative if said measured intensity ratio is greater than said threshold intensity ratio, verifying said encoded directory hologram.