Holographic behavior of a photopolymer at high thicknesses and high monomer concentrations: mechanism of photopolymerization

Abstract

One of the main problems involved in the development of holography is that of the recording material used. In this study the behavior of a photopolymer is analyzed when thicknesses greater than 100 μm are used. The photopolymer is made up of acrylamide as monomer, triethanolamine as radical generator, yellowish eosin as sensitizer and polyvinyl alcohol as binder. The main problem is that an increase in thickness produces more scattering and consequently a decrease in the diffraction efficiency. In this study we analyzed the influence of the concentration of monomer on scattering and found that an increase in the concentration reduces scattering. The behavior of the material varies as the concentration of acrylamide is increased. Two polymerization mechanisms compete and so the behavior of the photopolymer is not linear, the reaction is slower and the expected maximum efficiency is not reached. It has been demonstrated experimentally that when the recording intensity is reduced the photopolymer behaves in a linear way.