The Study On The Holographic Characteristics Of A Red-Sensitive Photopolymer

Photopolymer materials recently have gained attention because they have many advantages, which make them more suitable for applications as holographic storage materials. Especially in the photopolymerizable systems which were composed of acrylamide as monomer and Methylene Blue as photoinitiator, many researchers have improved the holographic characteristics by using all kinds of bifunctional monomers. But unfortunately there were many questions to some degree during recording the diffraction gratings, such as the poor homogeneity, the overmodulation of the refraction index, which would affect the quality of holograms recorded. So the photopolymerizabl- e system used in the experiments was consisted of acrylic acid and N,N'-methylenebisa- crylamide as monomers, triethanolmine as coinitiator, photoinitiated by Methylene Blue, and all the components were supported in a film of polyvinylalcohol. The fundamental holographic characteristics were studied in details by recording the transmission diffraction gratings.1. The homogeneity was studied by the variations of the transmittance as function of the exposure time and the diffraction efficiency as function of the exposure energy.2. The exposure characteristics were studied on the different exposure intensity, the different thickness, the spatial frequency and the beam ratio. So the holographic parameters, such as energetic sensitivity, modulation index and dynamic range, were attained in terms of the exposure characteristics of the different thickness of the materials.3. The dark diffusion of the photopolymer was studied.