Vector beams generated by microlasers based on topological liquid-crystal structures

Abstract

Structured light with designable intensity, polarization and phase fields is today of high relevance, with application ranging from imaging, metrology, optical trapping, ultracold atoms, classical and quantum communications and memory. Specifically, vortex and vector beams can be generated directly in the laser cavity, however, a controllable, geometrically simple and easy to manufacture laser microcavity that generates structured light on demand, especially tailored polarization, is still an open challenge. Here we show that tunable laser vector beams can be generated from self-assembled liquid-crystal (LC) micro-structures with topological defects inside a thin Fabry-P\'erot microcavity. The LC superstructure provides complex three dimensional birefringent refractive index profiles with order parameter singularities. The topology of the LC structures is transferred into the topology of the light polarization. The oriented fluorescent dye emission dipoles enable the selection of optical modes with a particular polarization, as enabled by the birefringence profile in the laser cavity. The proposed lasers have no principal limitation for realizing structured light with arbitrarily tailored intensity and polarization fields