Wide-angle giant photonic spin Hall effect

Abstract: Photonic spin Hall effect is a manifestation of spin-orbit interaction of light and can be measured by a transverse shift \lambda of photons with opposite spins. The precise measurement of transverse shifts can enable many spin-related applications, such as precise metrology and optical sensing. However, this transverse shift is generally small (i.e. \delta /\lambda <{10}^{-1}, \lambda is the wavelength), which impedes its precise measurement. To-date proposals to generate giant spin Hall effect (namely with \delta /\lambda >{10}^{2}) have severe limitations, particularly its occurrence only over a narrow angular cone (with a width of \Delta \theta <{1}^{\circ}). Here we propose a universal scheme to realize the wide-angle giant photonic spin Hall effect with \Delta \theta >{70}^{\circ} by exploiting the interface between free space and uniaxial epsilon-near-zero media. The underlying mechanism is ascribed to the almost-perfect polarization splitting between s and p polarized waves at the designed interface. Remarkably, this almost-perfect polarization splitting does not resort to the interference effect and is insensitive to the incident angle, which then gives rise to the wide-angle giant photonic spin Hall effect.