Recording holographic diffusers in a photopolymerizable glass

Diffusers are gaining importance in optics due to their versatile applications, such as enhancing light uniformity for illuminating objects, improving image visibility across a wider range of viewing angles, reducing glare, and controlling light distribution in displays and lighting systems. While conventional optical elements play a crucial role in modern instruments, they can be bulky and heavy. In contrast, holographic optical elements are more efficient, lightweight and can be miniaturized. However, the materials commonly used for volume holographic diffusers, often lack the durability needed for harsh environments such as aerospace, outdoor installations, automotive applications, industrial settings, and military and marine defense equipment. Holographic diffusers are typically recorded using photo-sensitive materials such as photopolymers, silver halide films, liquid crystals, and glass substrates. Recently, a promising photopolymerizable glass (PG) has been developed using the sol-gel technique, showing potential for improved robustness in challenging conditions. In this work, we present an investigation of holographic diffuser elements recorded in photopolymerizable glass. The motive of this work is to study the efficiency of diffusers recorded in photopolymerizable glass (PG), under various conditions. In this paper, we 1) Record diffusers in PGs by varying amount of nitric acid and 2) Study their diffusion efficiency for different exposure energy levels and observe their stability over time. This is the first time that such holographic diffusers recorded in photopolymerizable glasses have been reported. We observe that varying nitric acid amount leads to a differing response in the ability of the material to record diffusers for the same exposure conditions. We report the fabrication of PG diffusers with consistent layers which do not crack for an extended time period. Initial experiments with two compositions of the glass have shown promising results, and their efficiency is being stable and durable over time and potential pathways for further development.