Novel tunable optical properties of liquid crystals, conjugated molecules and polymers in nanoscale periodic structures as photonic crystals

Tunability of optical properties such as transmission and reflection by temperature and applied voltage has been demonstrated in synthetic opals and inverse opals like three-dimensional photonic crystals infiltrated with liquid crystals, conjugated molecules and polymers, in accordance with theoretical calculation. A new type of tunability based on uncoupled mode in a two-dimensional photonic band gap influenced by the field-dependent anisotropy in liquid crystals has also been demonstrated theoretically. Spectral narrowing and lasing have been observed in these opals infiltrated with conducting polymers and fluorescent dyes like three-dimensional photonic crystal and fluorescent dye-doped cholesteric and ferroelectric liquid crystal as one-dimensional photonic crystal. These lasing wavelength can be controlled by the applied voltage. Laser emission was also realized with conducting polymer on a surface relief grating formed on an azo-polymer film by interference optical beam.