Band-Edge Lasing with Cone-Shaped Emission from Flexible Nanoporous Cholesteric Liquid Crystal Polymer Films: Realization of Wavelength Tunability and Beam-Steering Capability

Dye-refilled nanoporous cholesteric liquid crystal polymer (DR-NPCLCP) films, fabricated by washing and refilling with dye-doped liquid crystals (DD-LCs), have emerged as promising templates for next-generation laser applications. Nevertheless, realizing flexible band-edge lasers in these devices remains challenging due to the intrinsic fluidity of liquid crystals. Here, we generated band-edge lasing from a freestanding DR-NPCLCP film, which revealed a circular polarization and a conical emission pattern. The as-prepared DR-NPCLCP film exhibited a 30 nm blue shift in its lasing peak wavelength after 6 days of ambient storage and showed no further shift thereafter. Moreover, the DR-NPCLCP films demonstrated excellent mechanical flexibility, showing an 8 nm red shift with increasing curvature and enabling beam steering by varying the excitation position on the bent films. A spatially tunable lasing peak with a 105 nm wavelength shift was achieved in gradient-pitch distributed DR-NPCLCP films, highlighting their versatility for advanced photonic applications.