Fig. 1. Chemical structures of chiral dopant R6N, liquid-crystal monomer RM257, and laser dye pyrromethene 597 and the fluorescence spectrum and absorption spectrum of laser dye PM597 in a nematic LC mixture.

Fig. 2. Optical path structure.

Fig. 3. Emission characteristics of lasers in the CLC and PSCLC. (a) Formation of the PSCLC, (b) the transmission and corresponding laser emission spectra of the dye-doped CLC and dye-doped PSCLC samples, and (c) the emission intensity of the lasers as a function of the pump energy.

Fig. 4. Electric-field-dependent broadening of the selective reflection band together with the electrical tunability of the emission wavelength of the laser. (a) The microphotographs observed under a polarized optical microscope and photographs of the dye-doped PSCLC under various voltages, (b) the transmission and corresponding laser emission spectra of the dye-doped PSCLC under various voltages with an excited pump energy of ∼1.4  μJ, and (c) the schematic illustration of the pitch distribution under different electric fields.

Fig. 5. (a) Lasing threshold at different wavelength positions and (b) lasing threshold distribution compared to fluorescence spectrum.

Fig. 6. Electric field response characteristics of the dye-doped PSCLC. (a) The relationship between the driving voltage and the peak wavelength of the laser, (b) the response speed of the laser, and (c) characterization of the electric field response stability when switching the electric field ON\OFF.

Fig. 7. Laser emission spectra of the dye-doped PSCLC measured for right-handed and left-handed circularly polarized (RCP and LCP, respectively) states under 0 V and 31 V, respectively.

Table 1. Peak Position and FWHM of the Laser Obtained by Different Drive Voltages