Two-Dimensional Polarization Gratings Realized via Photopatterning Liquid Crystals

Polarization gratings (PGs) are powerful tools to modulate an incident beam, boosting a wide range of applications in optics and photonics. Compared with one-dimensional (1D) PGs, two-dimensional (2D) PGs have an advantage of generating multiple beams, promoting the development of more functional applications. However, the variety of current 2D PGs is relatively limited, and the diffraction efficiency still needs improvement. Here, we propose a way to design multiple types of 2D PGs and improve the diffraction efficiency based on precisely controlled microstructures realized via photopatterning liquid crystals (LCs). The LC 2D PGs can efficiently generate polarization-controllable diffraction orders in different array patterns with a maximum diffraction efficiency of 80.7%, and the experiment results match well with simulations. The proposed LC 2D PGs with outstanding performance may facilitate their applications in spectroscopy, beam steering, optical communication, and modern display fields.