Efficient random lasing in topologically directed assemblies of blue-phase liquid crystal microspheres

Abstract

Controlling light flow in the directed-assembly of blue-phase liquid crystal (BPLC) microspheres with curvature boundaries and random domain of cubic lattices is a highly interesting photonic phenomenon. A strategy of efficient random lasing with resonant feedback based on a microemulsion comprising of BPLC, laser dye and block copolymer is presented here. BPLCs are produced with a microfluidic apparatus and confined in microspheres. These spatially-assembled dye-doped BPLC microdroplets are used as a source for the generation of laser light. Recurrent light flow inside the droplets comprising of face-centered cubic blue-phase boundaries provides omnidirectional lasing with efficient coherent feedback which is not supported by conventional resonators. The topologically directed assemblies of BPLC microspheres with explicit shape and symmetry are essential for reducing threshold and increasing Q-factor of laser emission. These results provide new avenues for a wide range of photonic applications.

Over 200 °C Broad‐Temperature Lasers Reconstructed from a Blue‐Phase Polymer Scaffold

“…[44] Therefore, probing light confinement in the BPLCs and using them as novel soft lasers are of great interest. Up to now, various BP lasers have been developed based on band-edge lasing, [42,45,46] distributed feedback lasing, [44] defect lasing, [47] and random lasing [48][49][50] using film confined in LC cells [51][52][53][54] or freestanding one. [42,43] Though much progress has been made on BP lasers in terms of the tunability of lasing wavelength under external stimuli, such as light, [55,56] electricity, [45,57,58] temperature, [48,51,54,[59][60][61][62] and mechanics, [63] the research focused on the working temperature of BP lasers is insufficient.…”