Fig. 1. Experimental setup for random laser pumping and detection device of DD-NLC ^[36]

Fig. 2. Emission spectra of 185 μm-thick cell^[36]. (a),(b) Emission spectra at different pump energies; (c) emission peak intensity and FWHM of spectra as a function of pumping energies

Fig. 3. Random laser spectra under different pump energies^[36]

Fig. 4. Influences of sample thickness on random laser^[36]. (a) Emission spectra with different thicknesses; (b) dependence of emission peak wavelength and average spacing of adjacent narrow spikes on thickness of wedged sample

Fig. 5. Working principle of PDLC^[45]. (a) Off state; (b) on state

Fig. 6. Emission spectra of DD-PDLC sample with different pump energies^[35]. (a) Pump energy is 20 μJ/pulse; (b) pump energy is 25 μJ/pulse; (c) pump energy is 28 μJ/pulse; (d) pump energy is 35 μJ/pulse; (e) pump energy is 47 μJ/pulse. Insets I and II are emission photo of DD-PDLC sample excited at 40μJ/pulse and a schematic diagram of a closed loop path of light formed by multiple scattering in a DD-PDLC sample, respectively

Fig. 7. Output intensity and FWHM of ASE spectra from DD-PDLC sample as functions of laser pump energy^[35]

Fig. 8. Schematic diagram of CLC molecular arrangement structure

Fig. 9. Normalized emission spectra from DD-CLC sample when optically excited at λ=532 nm for different applied electric fields^[67]. (a) 13 V/μm, 10 Hz; (b) 13 V/μm, 560 Hz; and (c) 13 V/μm, 5 kHz

Fig. 10. Optical textures, corresponding diffraction patterns and laser emission spectra of reconstructed CLC under different driven voltages^[68]. (a),(d),(g) Applied voltage of 2 V; (b),(e),(h) 3 minutes after applying voltage of 2 V; (c),(f),(i) applied voltage of 10 V followed by a sudden drop to 2 V

Fig. 11. Images of polarized optical microscope in reflected light mode and emission spectra^[79]. (a) Small size pure BPLC platelet (less than 3 μm); (b) intermediate size pure BPLC platelet (10--20 μm); (c) large size pure BPLC platelet (more than 30 μm); (d) intermediate size PS-BPLC platelet (6--15 μm)

Fig. 12. Laser spectra of PS-BPLC-wedged cell generated from positions of x=0, 2, 4, 6, 8 mm ^[81]

Fig. 13. Laser spectra of PS-BPLC-wedged cell at position of x=1 mm under different driven voltages^[81]

Fig. 14. Plots of laser emission intensity as a function of pump energy^[82]. (a) Laser threshold comparsion between PM597-doped BPI in 100 μm droplet and PM597-doped BPI in 100 μm cell; (b) emission spectra of PM597-doped BPI in 100 μm cell; (c) emission spectra of polyurethane encapsulated BPI droplets of 100 μm in diameter; (d) emission spectra collected across plane of optical pump confirm omnidirectionality of BP droplet

Fig. 15. Emission spectra of NPDDNLC sample under different conditions^[93]. (a) Peak intensity and FWHM as functions of pump energy in NPDDNLC sample; (b) peak intensity and FWHM as functions of pump energy in indye-and-Au-nanoparticle-co-doped ethanol samples; (c) emission spectra of NPDDNLC samples with the cell thickness of 10, 17, 26 μm at fixed pump energy of 8.39 μJ/pulse; (d) output intensity as a function of pump energy in NPDDNLC sample with the cell thickness of 10, 17, 26 μm; (e) spectra of NPDDNLC sample with the cell thickness of 10 μm at fixed pump energy of 17.87 μJ/pulse under different applied electric fields when polarization of the pump light is parallel to rubbing direction; (f) spectra of NPDDNLC sample with the cell thickness of 10 μm at fixed pump energy of 17.87 μJ/pulse under different applied electric fields when polarization of the pump light is perpendicular to rubbing direction. Insets show the output intensity as a function of the applied electric field from 0 V/μm to 2.1 V/μm in (e) and (f)

Fig. 16. Schematic diagram of DD-CLC random laser structure and experimental setup^[85]. (a) Schematic diagram of DD-CLC random laser structure, in which AgNPs is introduced on P-II glass substrate in liquid crystal cell; (b) generation and measurement devices of DD-CLC random laser, inset shows generated DD-CLC laser

Fig. 17. Performance of DD-CLC random laser with different sizes of AgNPs and temperatures^[85]. (a) Effects of different sizes of AgNPs on slope efficiency and laser threshold of DD-CLC random laser; (b) temperature-dependent band-edge laser peak positions from S-IV sample; (c) temperature-dependent wavelength shifts of long band-edge laser and short band-edge laser peaks