Exotic Photonic Spin Hall Effect from a Chiral Interface

The photonic spin Hall effect provides a quantitative way to characterize the spin-orbit interaction of light and enables many applications, such as the precise metrology, since this effect is featured with a spin-dependent transverse shift of the light beam. This transverse shift is generally nonzero during the reflection/transmission process, and it is sensitive to the polarization and the incident angle of the light beam. By contrast, here it is revealed that for the transmitted light, the transverse shift can be always zero and polarization-independent, irrespective of the incident angle. The underlying mechanism is that the conversion between the spin and orbit angular momenta of light is fully suppressed during the transmission process. Such an exotic photonic spin Hall effect occurs, if tpp=tss${t<^>{{\rm{pp}}}} = {t<^>{{\rm{ss}}}}$, tps=-tsp${t<^>{{\rm{ps}}}} = - {t<^>{{\rm{sp}}}}$, and theta t=theta i${\theta _t} = {\theta _i}$, where t stands for the transmission coefficient and its first (second) superscript represents the polarization of the transmitted (incident) light, and theta t${\theta _t}$ (theta i${\theta _i}$) is the transmitted (incident) angle. These transmission conditions are achievable, e.g., by exploiting an interface only with a chiral surface conductivity. Similarly, a polarization-independent photonic spin Hall effect is revealed for the reflected light.