Security optical data storage in Fourier holograms

We have proposed and demonstrated a holographic security storage system that is implemented with a shift multiplexing technique. The security function of this storage system is achieved by using a microdiffuser (MD) for random phase encoding of the reference beams. The apparatus of random phase encoding in this system offers an additional and flexible function during the recording processes. The system can generate holographic security memory or nonsecurity holographic memory via using the MD or not. The storage capacity and the average signal-to-noise value of the security storage system are 16 bits/μm ² and 3.5, respectively. Lateral shifting selectivity in this holographic security storage system is theoretically analyzed and experimentally investigated.