Noise-Free Readout In Holographic Storage By Concave Mirror

In photorefractive holographic storages, the superimposed holograms make the refractive index of the media irregular. The readout beam is scattered by the media and the noise is added onto the reproduced messages. In this paper, we introduced a simple way to suppress the noise caused by the superimposition. In our method, holograms were recorded by convergent reference beam. We made the convergent point of the beam overlap the curvature center of a concave mirror. The reflected beam from the concave mirror was used to readout the holograms. By this method, we suppressed the noise caused by superimposition and realized noise-free readout in holographic storage.