Enhanced tunable Bragg diffraction in large-pore inverse opals using dual-frequency liquid crystal

Large-pore TiO2 inverse opals were fabricated by atomic layer deposition in sintered polystyrene colloidal crystal templates and infiltrated with dual-frequency liquid crystal. The optical properties of the hybrid organic/inorganic structure were characterized by reflectance measurements of the Bragg peak, the position of which was tuned using a frequency dependent applied electric field. A 6nm blueshift was observed for frequencies less than 13kHz and a 13nm redshift for frequencies above 13kHz. These results demonstrate enhanced optical tunability in three-dimensional photonic crystals and are important for the development of active photonic devices.