Optical switch of diffractive light from a BCT photonic crystal based on HPDLC doped with azo component.

This study demonstrates an optical switch of the diffractive light from a body-centered tetragonal photonic crystal based on holographic polymer-dispersed liquid crystals that are fabricated using two-beam interference with multiple exposures. The liquid crystal-rich regions form the lattice points of the PC, which contains a liquid crystal/azo-dye mixture. The concentration of the cis isomer changes under laser light exposure; this change, in turn, modulates the effective index of the LCs, and then switches diffractive light.