Manipulation of photonic spin Hall effect with space-variant Pancharatnam-Berry phase

Observation of photonic spin Hall effect (SHE) manifested by spin-dependent splitting of light in a dielectric-based birefringent metasurface is reported experimentally. By designing the metasurface with homogeneous phase retardation but space-variant optical axis directions, we govern the photonic SHE via space-variant Pancharatnam-Berry phase originated from the local polarization manipulation of the metasurface, essentially, the spin-orbit interaction between the light and the metasurface. Modulating the polarization distribution of the incident light and/or the structure geometry of the metasurface, the photonic SHE could be tunable. This type of metasurface offers an effective way to manipulate the spin-polarized photons and a route for spin-controlled nanophotonic applications.