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 3D lasing is due to the stimulated emission of light from the dye molecules in the liquid crystal. The wavelength depends solely on the period of the cholesteric and varries with temperature. Millions of microlasers can be formed by mixing a liquid crystal, a laser dye and a carrier fluid, thus providing microlasers for soft-matter photonic devices.
COBISS.SI-ID: 24377895
The topological properties and interactions of nano colloids in the nematic liquid crystal 5CB have been studied. We find that silica particles, surface-functionalized with DMOAP induce dipolar structure of 5CB around them even for 125 nm diameter. These are accompanied with clearly resolvable hyperbolic point defect and behave as a much bigger particles because of the elastic distortion. This has a consequence that the binding energy of dipolar nanocolloids is as high as 600 kT for a 125 nm colloid and is practically size-independent from 125 nm to 500 nm.
COBISS.SI-ID: 24172327