Characterization of Holographic Gratings in PVA/AA Using Coherent Nanosecond Laser Exposure

This work investigates the performance of a polyvinyl alcohol/acrylamide-based photopolymer (PVA/AA) under pulsed and continuous-wave (CW) laser exposure for holographic recording. Using a versatile setup that allows direct comparison between both regimes, diffraction efficiency (DE), angular responses, and material parameters were analyzed. Comparable maximum DE was achieved with both CW and pulsed laser exposure; however, the pulsed regime produces stronger attenuation along the grating depth, which emphasizes the need to lower the dye concentration. Furthermore, the temporal evolution of DE reveals a smaller influence of oxygen inhibition under CW exposure. Finally, second-order angular reconstructions confirm that pulsed gratings exhibit a better sinusoidal modulation, especially at low frequency rates. These results enhance the understanding of how pulsed exposure affects holographic recording and open pathways for optimizing photopolymer systems in advanced technologies.