Photochemical switching behavior of azofunctionalized polymer liquid crystal/SiO2 composite photonic crystal

A photochemically tunable photonic crystal was prepared by infiltrating azopolymer liquid crystal in a SiO2 inverse opal structure. The SiO2 inverse opal film obtained reflected a light corresponding to the periodicity as well as the refractive indices of the inverse opal structure. Linearly polarized light irradiation shifted the reflection band to longer wavelength more than 15nm. This is caused by the formation of anisotropic molecular orientation of the azopolymer. The switched state was stable in the dark, and the reversible switching of the reflection band can be achieved by the linearly and circularly polarized light irradiations.