Patent ID: 9703260
Date: 2017-07-11
CPC Classifications: G03H,G11B

Claim:
1. A method for retrieving information stored in a holographic storage medium, the method comprising: illuminating at least one hologram in the holographic storage medium with at least one probe beam so as to generate at least one reconstructed signal beam representing at least some information stored in the holographic storage medium; detecting a plurality of images, each image in the plurality of images comprising a respective spatial interference pattern in a plurality of spatial interference patterns, the plurality of spatial interference patterns comprising (i) a first spatial interference pattern generated by interference of the at least one reconstructed signal beam with at least one local oscillator beam at a first phase difference between the at least one reconstructed signal beam and the at least one local oscillator beam and (ii) a second spatial interference pattern generated by interference of the at least one reconstructed signal beam with the at least one local oscillator beam at a second phase difference between the at least one reconstructed signal beam and the at least one local oscillator beam; and combining the plurality of spatial interference patterns to form a representation of the at least some information, the representation being substantially free of common intensity noise, wherein the plurality of spatial interference patterns comprises n>2 spatial interference patterns and wherein there is a difference modulo 2π/n between the first phase difference and the second phase difference.