Optical Switching of a Birefringent Photonic Crystal

Photonic crystals with photocontrollable polarization-dependent stop-bands are fabricated by infiltrating photoresponsive nematic liquid crystals into a stretched polymer inverse opal. When the liquid crystal is in a nematic phase, molecules aligned along the stretching axis generate an optical birefringent effect, which disappears when the liquid crystal is in an isotropic phase. The two states can be reversibly switched by UV-vis light irradiation.