Liquid microlenses and waveguides from bulk nematic birefringent profiles.

We demonstrate polarization-selective microlensing and waveguiding of laser beams by birefringent profiles in bulk nematic fluids using numerical modelling. Specifically, we show that radial escaped nematic director profiles with negative birefringence focus and guide light with radial polarization, whereas the opposite - azimuthal - polarization passes through unaffected. A converging lens is realized in a nematic with negative birefringence, and a diverging lens in a positive birefringence material.

Generation of vector beams with liquid crystal disclination lines.

We report that light beams, guided along liquid crystal defect lines, can be transformed into vector beams with various polarization profiles. Using finite-difference time-domain numerical solving of Maxwell equations, we confirm that the defect in the orientational order of the liquid crystal induces a defect in the light field with twice the winding number of the liquid crystal defect, coupling the topological invariants of both fields. For example, it is possible to transform uniformly polarized light into light with a radial polarization profile.