This paper presents an optimisation of a photopolymer formulation for improved refractive index modulation and sensitivity of the layer. An increase in the acrylamide concentration of 66% resulted in 50% higher refractive index modulation with values reaching 5 × 10−3 in 40 micron layers.
Faster recording times are an important consideration for the commercialization and mass production of photopolymer devices [1]. Higher production rates and lower costs are some of the main advantages. Altering the initiator is expected to have an effect on the material’s sensitivity and thus on recording time.
Several initiators were compared, triethanolamine (TEA), methyldiethanolamine (MDEA) and dimethylethanolamine (DMEA). It was found that holograms recorded with MDEA as the initiator recorded 58% faster over TEA based photopolymer at larger layer thicknesses.
The stability of the photopolymer was also tested with different protective coatings when subjected to UV light. The properties exhibited by this photopolymer composition make it a promising candidate for development of solar concentrating applications; however improvements to the durability in conditions of UV radiation will have to be made before it is suitable for solar concentration.
