Spatial frequency multiplexed diffuse-object holograms of N object waves recorded in bleached silver-halide emulsions

Abstract

In several important applications of holography such as optical information storage it is necessary to multiplex several functions or many optical components in the same thin film recording material. An optically recorded multiple grating hologram can be encoded either sequentially or simultaneously, but for the same total exposure, the diffraction efficiency of sequentially recorded holograms is lower than for a simultaneous hologram. If the number of multiplexed gratings is increased, and the angles between these gratings are reduced, the recorded object beam should resemble the field from a diffuse-object. However, in actual holograms, noise is present and it seriously limits that density. That is why maximum storage density is a function of the hologram's signal-to-noise ratio (SNR). For all of these reasons it is important to analyze the characteristics of diffuse-object holograms in the field of information storage. In this communication we present experimental results on the influence of the number of object waves and their spatial distribution on diffraction efficiency and SNR for bleached holograms recorded by using a collimated reference wave and N divergent object waves. The N object waves are interfered with the reference wave by using a simultaneous recording (coherent recording).