Generation of geometric phase optical elements using photoalignment technology of liquid crystals and progress of polarization optical system

In photonics, the growing demand to manipulate polarized optical signals, driven by recent advancements in light sensing, imaging, laser processing, and massive optical communications with uniform polarization, has sparked interest in Geometric Phase Optical Elements (GPOEs) for polarization control. Unlike conventional phase or amplitude optical devices, polarization photonic devices utilize Geometric Phase (GP) modulation in space to locally modify the polarization state of light passing through them. Liquid Crystals (LCs) are emerging as a crucial material class due to their structural flexibility and high orderliness at molecular and bulk levels, enabling the generation of essential polarization photonic functions. The success of LCs in polarization photonics relies on exploiting unique electrical and optical properties, as well as advancing the physics, chemistry, and materials science required for photo-alignment and fabrication of three-dimensional anisotropic structures. This review provides an overview of our past and current studies in polarization photonics, covering both fundamentals and applications.