The spin Hall effect (SHE) of light originates from the spin-orbit interaction, which can be explained in terms of two geometric phases: the Rytov-Vladimirskii-Berry phase and the Pancharatnam-Berry phase. Here we present a unified theoretical description of the SHE based on the two types of geometric phase gradients, and observe experimentally the SHE in structured dielectric metasurfaces induced by the PB phase. Unlike the weak real-space spin-Hall shift induced by the SRB phase occurring at interfacial reflection/refraction, the observed SHE occurs in momentum space is large enough to be measured directly.
Dielectric metasurfaces with spatially varying birefringence and high transmission efficiency can exhibit exceptional abilities for controlling the photonic spin states. We present here some of our works on spin photonics and spin-photonic devices with metasurfaces. We develop a hybrid-order Poincaré sphere to describe the evolution of spin states of wave propagation in the metasurface. Both the Berry curvature and the Pancharatnam-Berry phase on the hybrid-order Poincaré sphere are demonstrated to be proportional to the variation of total angular momentum. Based on the spin-dependent property of Pancharatnam-Berry phase, we find that the photonic spin Hall effect can be observed when breaking the rotational symmetry of metasurfaces. Moreover, we show that the dielectric metasurfaces can provide great flexibility in the design of novel spin-photonic devices such as spin filter and spin-dependent beam splitter.
The photonic spin Hall effect (SHE) is generally believed to be a result of an effective spin-orbit coupling, which
describes the mutual influence of the spin (polarization) and the trajectory of the light beam. The photonic SHE
holds great potential for precision metrology owing to the fact that the spin-dependent splitting in photonic SHE
are sensitive to the physical parameter variations of different systems. Remarkably, using the weak measurements,
this tiny spin-dependent shifts can be detected with the desirable accuracy so that the corresponding physical
parameters can be determined. Here, we will review some of our works on using photonic SHE for precision
metrology, such as measuring the thickness of nanometal film, identifying the graphene layers, detecting the
strength of axion coupling in topological insulators, and determining the magneto-optical constant of magnetic
We present a theoretical and experimental investigation of the spin Hall e®ect (SHE) of light in graphene. When
a light beam impinges onto graphene-prism interface near Brewster angle, an enhanced and switchable spin-
dependent splitting can be detected via the signal enhancement technique known from weak measurements. Our
preliminary experimental results show that the SHE of light can become an advantageous metrology tool for
characterizing the refractive index of graphene. In addition, the SHE of light may have a potential of probing
the spatial accumulations of spin electrons in the graphene, which builds a bridge between electronic SHE and