3-dimensional characterization of thick grating formation in PVA/AA based photopolymer

Large thickness is required in holographic recording materials to be used as holographic memories. Photopolymers have proved to be a good alternative to construct holographic memories. Nevertheless, modeling the behavior of thick layers poses some problems due to high absorption of the dye, as discussed in previous papers. In this study, the gratings stored in photopolymers based on polyvinylalcohol/acrylamide (PVA/AA) are analyzed considering the attenuation of light in depth. This is done by fitting the theoretical results, predicted by a model that considers this effect, to the experimental results obtained using diffraction gratings recorded in PVA/AA based photopolymer. In order to determine the diffraction efficiency at the first Bragg angle, an algorithm based on the rigorous coupled wave theory is used. Also, the characteristics of the gratings obtained using different recording intensities are analyzed, and the effective optical thickness is seen to increase as the intensity is increased.This work was supported by the “Ministerio de Educación y Ciencia”, Spain, under projects FIS2005-05881-C02-01 and FIS2005-05881-C02-02