Stretching the sensitivity and stability of an acrylamide based photopolymer material with mixture of dyes

The limited absorption range of photopolymers in the visible region was always a matter of concern due to their wide-spread application in the field of holography. The present work has investigated the possibility of extending the limited absorption range towards the entire visible range by simple modifications in the photopolymer composition so that panchromaticity can be invoked in the material. Here modification was done on already developed photopolymer material by adding another photosensitizer. Studies showed that holographic performance was improved to a great extent. It was possible to record gratings with blue, green and red wavelengths in 130 µm thick films with more than 80% diffraction efficiency (DE) creating a refractive index modulation of ∼1.7 × 10−3 at exposure energy of 50 mJ/cm2. This material will be a good candidate for data storage and color holographic applications. One of the remarkable findings was that the storage and shelf life of the material could be extended compared to other photopolymer materials. This material could be used to write gratings with 70% DE even after 12 months of storage. Thus, addition of a second photosensitizer not only extended the absorption range, but also the shelf life of the photopolymer.