Real-time interferometric characterization of a PVA based photopolymer

Abstract

Recently, we have proposed the application of interferometric techniques, both in transmission and in reflection, to characterize in real-time the modulation performance of the photopolymers. In this work we use this approach to characterize the optical modulation properties of a polyvinyl alcohol/acrylamide (PVA/AA) photopolymer. A double beam interferometer is constructed, both in transmission and in reflection, in combination with the setup to expose the recording material. Some benefits are provided by this approach: direct calculation of the properties of the material is possible, index and surface modulation can be decoupled, and additional information can be obtained since the results are not influenced by diffusion processes. With this scheme we mainly characterize the properties at very low spatial frequencies, which can be useful to analyze the applicability of holographic recording materials in another range of applications, such as recording of diffractive optical elements (DOEs). Comparison with the conventional holographic characterization shows significant differences.