Guest Editorial Special Issue on Progress in Photonic Spin-Orbit Interaction (SOI)

The papers in this special section focus on progress in photonic spin-order interaction (SOI). Spin and orbital angular momenta (SAM and OAM) are two distinct components of light beams. The SAM is associated with polarization of the light, whereas the OAM is related to a helical wave front, which has an azimuthal dependence of phase and can be described by a topological charge. These two different forms of AM are independent of each other within the boundaries of paraxial propagation in space. However, they become intertwined when the light beam is traveling through inhomogeneous and anisotropic media, or is tightly focused beyond the paraxial condition, leading to the photonic SOI. The photonic SOI underpins many optical processes, thus playing a significant role in the modern optics. The photonic SOI has led to such intriguing optical phenomena, as photonic spin Hall effect, orbit Hall effect, spin-orbit Hall effect, optical Skyrmion, and interconversions between the spin and the orbital terms, among others. Importantly, the photonic SOI also holds promise for potential applications in nanophotonic devices, quantum information processing, precise metrology, and optical (including quantum) sensing.