The Application of Heat Treatment in the Formation of Relief-Phase Holographic Structures on Dichromed Gelatin

Abstract

A new method of formation of relief-phase holographic structure on dichromated gelatin (DCG) layers has been proposed. The method is based on two types of alternative effects on gelatin: structuring by selective light tanning by coherent He–Cd laser radiation and destruction by short-wave UV radiation. A time-shortened water treatment of samples interrupted by an isopropanol bath was previously proposed to obtain highly effective holographic relief structures in the region of high spatial frequencies up to 1500 mm–1. In this paper, it has been proposed to abandon the water treatment of dichromated gelatin layers and replace it by heating the sample during its processing with short-wave UV radiation. In the course of experiments, a steady increase in the diffraction efficiency has been obtained regardless of the spatial frequency and dichromated gelatin layer thickness, which has been explained by the formation of a relief holographic structure because of the evaporation and shrinkage of gelatin areas degraded by UV radiation under the influence of high temperature.