Effects of Film Nonlinearities in Holography

Abstract

A study of the effects of photographic nonlinearities in recording coherent wavefronts is reported. Particular emphasis is placed on holography using the two-beam interferometry technique. A phenomenological model which provides the mathematical formulation for describing the effects of nonlinearities is described. The model includes a zero-memory nonlinearity which represents experimentally derived transmittance-exposure curves for various photographic emulsions. An analysis of this model reveals many interesting phenomena which are supported experimentally. In particular, the nonlinearity of the film generates false targets, causes weak signal suppression, and can introduce additional noise as a result of spectral folding. Experimental results, verifying the analysis, are presented.