Photonic spin Hall effect: Physics, manipulations, and applications

The photonic spin Hall effect (PSHE), as an exotic analogy to the spin Hall effect in electronics, is induced by the spin-orbit interaction of light and manifests itself as a spin-related splitting of left- and right-handed circularly polarized beams. Recently, the PSHE has been revealed and explored in a wide range of fields such as optical interfaces, metasurfaces/metamaterials, near-field optics, topological and disordered systems, as well as non-Hermitian photonics. Significantly, the PSHE provides the unique spin degrees of freedom to flexibly control light, which has enabled tremendous applications in precise metrology, spin-based nanophotonic devices, and mathematical operations, to name only a few. Also, new methods to manipulate and enhance this effect have been actively pursued. Here, we provide a comprehensive review of the key aspects in the PSHE, especially the underlying physics, new techniques of manipulations, and emerging applications. Our review can not only help new researchers of this field in a timely manner but also inspire more efforts in making and engineering PSHE-based devices in coming years.