Method for the evaluation of the effects of film nonlinearities on the holographic image

Abstract

An exact method for the evaluation of the images reconstructed from holograms recorded in nonlinear media is reported for what is to the author’s knowledge the first time. The method is based on the use of the nonlinear holographic characteristics of the recording material without any limitation on the range of bias exposures and visibilities. These characteristics have been obtained by fitting analytical functions to experimental data describing practical recording materials. Numerical calculations have been carried out for high-numerical-aperture thin amplitude holograms of a five-element Ronchi ruling. The contrast of the reconstructed image as a function of the bias exposure and beam ratio is computed.