Simplified Processing Method of Dichromated Gelatin Derived from Agfa 8E75HD Plates

Abstract

Dichromated gelatin (DCG) is one of the best recording materials for phase volume holograms. Since DCG has large refractive-index modulation, high resolution, high diffraction efficiency (DE), and good signal-to-noise ratio, it is suitable for preparing holographic optical elements. Several papers on the hologram formation mechanism in DCG have been reported in the literature.[1-5] The simplest way to obtain a good hologram is by use of photographic plates, dissolving the silver halide in a fixing bath, and sensitizing it with a solution of ammonium dichromate. Upto now, most of the works has been done using the gelatin layer of Kodak 649F plates. Oliva et al.,[8] presented the holographic characteristics of the DCG plates obtained from Agfa 8E75HD plates. The processing procedures for preparing high-quality DCG holographic optical elements (HOEs) developed by Oliva, however, are tedious, since it takes at least 12 hours to process one HOEs. In this work, we present very simple method for making highly efficient DCG hologram starting with Agfa 8E75HD plates. Beginning with Agfa 8E75HD plates, the complete processing time including preprocessing, sensitization, and development is just 2 hours. In addition, DCG hologram has a high DE of 81.5%.