Photoalignment-induced two-dimensional liquid crystal polarization structure via multi-beam polarization interferometry

A two-dimensional (2D) pure polarization pattern via four-beam polarization interferometry of circularly polarized beams is demonstrated both theoretically and experimentally. The polarization orientation of the interference pattern is recorded by an azobenzene photoalignment layer and transferred to liquid crystal (LC), enabling the fabrication of a 2D liquid crystal (LC) chiral structure. This structure behaves as a 2D LC polarization grating (LCPG) that can generate multiple polarization-selective diffraction beams of orthogonal polarization states with high efficiency. This 2D LCPG provides an effective way to distribute an optical signal into multiple receivers by both incidence polarization control and external electric field, therefore offering potential applications on multi-channel optical communication and information processing.