Fig. 3: SH vector vortex beam generated by FNLC q-plate.
From: Nonlinear geometric phase coded ferroelectric nematic fluids for nonlinear soft-matter photonics
a Schematic illustration of the SH optical response of an FNLC director for the incident FW with linear polarization. The LC director is counterclockwise rotated by an angle α around the z-axis (facing the direction of light propagation). b Illustration of the light-matter interaction geometry between the linearly polarized FW and the nonlinear LC q-plate. LP: linear polarization. c Polarized optical microscopic texture of the LC q-plate with the topological charge of 1. d, e Polarized optical microscopic textures of the LC q-plate under an in-plane electric field. Scale bar: 50 μm. f–j Intensity distributions of the FW and SH vector vortex beams. Analyzed SH vector vortex beams are in the second and third panels of (g) with the fast axes of the polarizer and analyzer denoted by black and blue arrows, respectively. White dotted lines in (g) indicate the extinction regions. White single-sided arrows in (f) indicate the polarization distribution of output FW. White double-sided arrows represent the incident polarization of FW (ϕ = 0°, 0°, 45°, 90°, and 135°). Yellow arrows in (g–j) indicate the polarization distribution of the SHWs.
