Characterization of optically switchable holographic polymer-dispersed liquid crystal transmission gratings

This study characterizes the all-optical switching effect in holographic polymer-dispersed liquid crystal (H-PDLC) transmission gratings. Before light irradiation, the intensity of the first order diffraction was set to maximum while the zero order (0th) transmission was minimized. Upon light irradiation, the first order spot size of the He–Ne laser decreased while the zero order spot size increased. [Display omitted] ► We characterize optically switchable transmission gratings. ► The grating is fabricated by holographic polymer-dispersed liquid crystal technique. ► The all-optical switching is generated by the doped azobenzene-derived LC (azo-LC). ► The photoisomerization of azo-LC changes the refractive index of phase-separated LC. ► 78% tunable efficiency and 0.5s response time are achieved under 9 mW/cm 2 laser power. This study characterizes the all-optical switching effect in holographic polymer-dispersed liquid crystal transmission gratings. The light-induced switching behaviors of these structures are due to the doped azobenzene-derived LC (azo-LC), which changes the refractive index of phase-separated LC within the polymer composite. This study also optimizes the polymer-dispersed liquid crystal formulation containing 15 wt.% azo-LC and 35 wt.% nematic LC to achieve a grating performance with a tunable diffraction efficiency of 78% and a fast switching-on time (0.5 s) with a relatively small light stimulus of 9 mW/cm 2.