Study on the mechanism of dark enhancement in phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for holographic recording

The dark enhancements with various exposure energies are studied in thick PQ/PMMA photopolymer. Considered the weak molecules diffusion of PQ component and the grating detuning, a new mechanism of dark reaction is proposed to explain the dark enhancement. Moreover, the influences of dark reaction on Bragg angular selectivity and grating recording are analyzed. The results are beneficial to the practical holography application.