Hologram Recording With A New Photopolymer System

Abstract
Holography with a new photopolymer system, Polaroid DMP-128, is described. Films of DMP-128 from an aqueous solvent are coated on either solid or flexible substrates. The resulting films, when stored dry, have a shelf life that exceeds nine months. The dry films are inactive and must be incubated for a few minutes in an environment of approximately 50% RH before laser expo-sure. Recording is possible with either blue (442 nm, 488 nm), green (514 nm), or red (633 nm, 647 nm) laser light. Exposure of 5 mJ/cm2 is sufficient for high diffraction efficiency (80% to 95%) transmission holograms, while 30 mJ/cm2 is required for bright reflection holograms. It is not necessary to exclude atmospheric oxygen during hologram recording. Refractive index modulation of 0.03 is routinely achieved. After laser exposure a uniform white-light illumination is used to complete the photopolymerization. A single processing bath yields holograms with good environmental stability. An additional processing bath yields images with exceptional resistance to high humidity.