Bragg reflective polychromatic vector beam generation from opposite-handed cholesteric liquid crystals

Abstract

In this Letter, a method of stacking two opposite-handed cholesteric liquid crystals (CLCs) with the same pitches and the same surface azimuthal angles to generate vector beams from homogeneous linear polarization is proposed. By this means, vector beams with arbitrary orders can be generated based on point-to-point photo-alignment technology. In our experiment, radially polarized, azimuthally polarized, and high-order vector beams with high efficiency have been generated. The device operates light polarization within the Bragg reflection polychromatic bandgap. Our proposal also provides the possibility to generate reflective hybrid-order Poincaré beams if these two CLC layers are impressed with different topological charges. It has great potential for reflective photonics applications in high-resolution imaging, focusing, and information processing.