Enhanced Tunable Bragg Diffraction in Large-Pore Inverse Opals Using Dual-Frequency Liquid Crystal

Large-pore Ti O2 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 6 nm blueshift was observed for frequencies less than 13 kHz and a 13 nm redshift for frequencies above 13 kHz. These results demonstrate enhanced optical tunability in three-dimensional photonic crystals and are important for the development of active photonic devices.