Random modulation in high-density holographic data storage and correlation recognition system

Abstract

In the holographic data storage system, a shifting diffuser is employed in the reference beam to realize dynamic speckle multiplexing, while another vibrating diffuser is placed in the object beam to realize speckle modulation. These two methods can enlarge the storage capacity with high signal-to-noise rate. Speckle multiplexing can suppress the crosstalk due to multiple longitudinal modes of the small DPL laser. And speckle modulation in volume holographic correlators can suppress the diffraction sidelobes of output correlation signal along both vertical and horizontal direction. Another advantage of the speckle multiplexing and the speckle modulation is that the angular selectivity and the correlation peak are not sensitive to the thickness of the hologram. Finally a demonstration platform of compact holographic storage and correlation recognition system is briefly introduced in this paper.