Fig. 1. Sketch of the experimental setup.

Fig. 2. (a) Reflection spectra and (b) transmission spectra for dye-doped planarly oriented CLC samples with different concentrations of the chiral agent CB15. The black solid curve is the fluorescence spectrum of PM597.

Fig. 3. Texture patterns of samples with different concentrations of the chiral agent CB15 in nonoriented cells observed by a POM with a 20× objective. (a) S1*, (b) S2*, (c) S3*, (d) S4*, (e) S5* in reflection mode. (f)–(j) Corresponding textures in transmission mode. All cell gaps are 230 μm.

Fig. 4. Spectra (a)–(e) represent emission for different disordered samples S1*, S2*, S3*, S4*, S5*, respectively. (f) The dependence of the peak intensities of the random lasing on the pump energy for different concentrations of the chiral agent. The black lines in spectra (g)–(k) are the emission spectra corresponding to spectra (a)–(e); the red lines in spectra (g)–(k) are reflection spectra for oriented CLC samples, respectively.

Fig. 5. (a) Emission spectra for different pump positions across the sample S2*. (b) Emission spectra of the sample S2* for different single-pump shots.

Fig. 6. Working mechanism of RL in a dye-doped CLC random system with a selective reflection band (a) coinciding with the fluorescence peak and (b) far away from the fluorescence peak. The yellow arrows represent the scattering light beams at the wavelength of the fluorescent peak. The helical axes of microdomains designated by red arrows exhibit a small angle with the direction of the incident light, which results in enhanced reflective behavior when the selective reflection band of the sample overlaps with the fluorescence peak of the dye. The dark and light yellow arrows represent strong and weak feedback, respectively.