Thermally tunable random laser in dye-doped liquid crystals

A thermally tunable random laser in dye-doped liquid crystals (DDLCs) is reported. The gain medium of PM597 dye-doped E7 nematic LC is injected into a glass cell. The experimental results show that the random lasing is still obtained when the cell temperature becomes higher, even above the nematic–isotropic transition, and that its polarization changes at the same time. Temperature has little effect on the full width at half maxiumum of the random lasing. The center wavelength of the random lasing shifts from 575.69?nm to 593.43?nm when the temperature increases from 25.5°C to 148°C. Meanwhile, a random laser based on a solution of laser dye is first reported in this article. The reasons are possibly that nanoparticles consisting of dye molecules provide a new scattering mechanism in both solution and isotropic phase.