Large in-plane asymmetric spin angular shifts of a light beam near the critical angle

The photonic spin Hall effect (SHE) manifests itself as the transverse and in-plane spin-dependent shifts of a light beam. Normally, the spin shifts are tiny due to the weak spin-orbit coupling. Therefore, it is very important and interesting to explore some effective methods for enhancing this phenomenon. In this Letter, we theoretically propose and experimentally verify a simple method for obtaining large and asymmetric in-plane spin angular shifts when an arbitrary linearly polarized beam reflects near the critical angle (for total internal reflection). The universal expressions of spatial and angular shifts are deduced. Remarkably, by modulating the incident and polarization angles, the left- and right-handed circularly polarized components can be distinguished directly.