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

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.