Spatially tunable laser emission in dye-doped photonic liquid crystals

A spatially tunable laser emission of the dye-doped cholesteric liquid crystal (CLC) cell using a one-dimensional temperature gradient is demonstrated. The photoexcitation of dye-doped CLC device using a frequency-doubled pulsed Nd: yttrium-aluminium-garnet laser gives rise to laser emission in the yellow-red spectral range. The lasing wavelength is widely tunable from 577 to 670 nm by shifting the position of the dye-doped CLC cell with respect to the pumping beam. The lowest excitation energy and maximum lasing efficiency occur at lambda similar to 605 nm which corresponds to the peak fluorescence emission of the dye. (c) 2006 American Institute of Physics.