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5 January 2004Tunable lasing in doped liquid crystals with one-dimensional periodic structure
Various types of tunable lasing in dye-doped liquid crystals with one dimensional periodic structure have been demonstrated. An electrical tuning of lasing wavelength has been demonstrated in a dye-doped chiral smectic liquid crystal mixture with a short pitch helical structure which is so-called ferroelectric liquid crystal (FLC). Waveguide configuration of FLC laser has also been proposed, also in which the lasing wavelength widely can be tuned upon the electric field. The electrically tunable lasing has been observed also in a focal conic structure of dye-doped cholesteric liquid crystal. This laser action is based on a helix micro-cavity in focal conic domains. Optically pumped distributed feedback lasing has been proposed in a dye-doped nematic liquid crystal (NLC) waveguide by holographic excitation, in which continuous tuning of the lasing wavelength is performed upon applying electric field. Electrical tuning of the wavelength of the defect mode lasing in a one-dimensional periodic structure has been demonstrated using a dye-doped NLC as a defect layer in the periodic structure. Lasing wavelength is widely tuned upon applying the electric field, which is due to the refractive index change in the defect layer caused by the field-induced realignment of the NLC molecules.