Silver-halide sensitized holograms and their applications

Abstract

Silver-halide sensitized gelatin (SHSG) has the sensitometric and spectral response of silver halide emulsions and the holographic characteristics of dichromated gelatin, and therefore when properly processed it has little scattering and absorption. SHSG is one of the most promising techniques today for the fabrication of transmission holographic optical elements. In this paper we first review the mechanism of hologram formation in SHSG. The most important steps of processing -the influences of the developer on the modulation transfer function and of bleaching on the diffraction efficiency- are analyzed. Holographic characteristics such as exposure, sensitivity, resolution, thickness change and enviromental stability are pointed out. Through optimized processing it has been able to fabricate holographic optical elements, including a holographic scanner and different off-axis holographic lenses. These are analyzed from the point of view of the recording material.