3D microlasers from self-assembled cholesteric liquid-crystal microdroplets.

We demonstrate a tunable and omnidirectional microlaser in the form of a microdroplet of a dye-doped, cholesteric liquid crystal in a carrier fluid. The cholesteric forms a Bragg-onion optical microcavity and the omnidirectional 3D lasing is due to the stimulated emission of light from the dye molecules in the liquid crystal. The lasing wavelength depends solely on the natural helical period of the cholesteric and can be tuned by varying the temperature. Millions of microlasers can be formed simply by mixing a liquid crystal, a laser dye and a carrier fluid, thus providing microlasers for soft-matter photonic devices.