Photopolymers, especially acrylate-based ones with low cost and simple preparation, are promising materials for high-efficiency holographic gratings. However, it is still challenging to achieve high-performance gratings, due to the influences of many factors. In this work, we found that the dark reaction plays a critical role. The effect of the dark reaction on the optical properties of holographic gratings was investigated. Experimental results reveal that the diffraction efficiency of the gratings can be improved by a factor of three by involving the dark reaction process, and the highest diffraction efficiency for gratings can reach 97.8% after optimization. Therefore, the dark reaction can greatly enhance the optical performance of acrylate-based holographic gratings and other optical elements, thus holding great potential for many applications.
