Noise reduction techniques for holographic information storage

Abstract

The effects of wavefront conditioning on the performance of holographic optical data storage systems is investigated. The physical origins of various noise mechanisms which degrade the SNR of the holographic storage are studied for the thin phase (DCG) and the photoreflective crystal (LiNbO₃) recording materials. Dependence of the noise on various system parameters such as focal length, pixel size, number of pixels and material parameters are studied. An algorithm is developed to design pseudorandom phase masks which can improve the signal-to-noise ratio for a given system. The noise reduction by using pseudorandom phase mask and a Galilean configuration are investigated theoretically and experimentally. Significant improvement to the signal-to-noise ratio of holographic storage systems is demonstrated experimentally.