Effect of liquid crystal concentration on the lasing properties of dye-doped holographic polymer-dispersed liquid crystal transmission gratings

Optically pumped single-mode lasing was achieved from a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran dye-doped holographic polymer-dispersed liquid crystal transmission grating with various liquid crystal concentrations, which played an important role in the lasing generation and wavelength selection. With the decrease of the liquid crystal concentration, under the excitation of a frequency-doubled Nd:yttrium aluminum garnet laser operating at 532nm, the lasing wavelength was blueshifted, and the full width at half maximum of the lasing peak became narrower. The lowest threshold pumping energy was found to be about 5μJ∕pulse at a liquid crystal concentration of 19.7wt%. The lasing emission was thermally switchable due to the change of the refractive index modulation.