Patent ID: 6850346

Claim:
A method for storing a sequence of digital page data into a holographic medium which moves continuously and linearly, the method comprising the steps of: splitting a coherent monochromatic beam into a reference beam and a signal beam; sequentially modulating the signal beam with the digital page data to generate a modulated signal beam; transforming the reference beam into a first and a second complex reference beam; and converging the modulated signal beam and the first and the second complex reference beams on the holographic medium to generate a sequence of first and second interference patterns to be sequentially stored in the holographic medium, respectively, wherein a shift selectivity of the first complex reference beam is larger than that of the second complex reference beam so that the second interference patterns are used as servo patterns to sequentially determine where the first interference patterns have been stored, and wherein the shift selectivities of the first and the second complex reference beams are minimum movements of the holographic medium relative to the first and the second complex reference beams which cause little correlations between every two neighboring first and second interference patterns, respectively.