Tunable quantized spin Hall effect of light in graphene

Abstract

The spin Hall effect of light is an appealing toolset for metrology that holds incredible potential for precision measurements due to its high sensitivity to the refractive index and nanostructure physical parameters. Here, we theoretically examine the quantized spin Hall effect of light on the surface of a monolayer graphene–substrate system subjected to an external perpendicular magnetic field. We discuss the impact of Landau levels induced by the external magnetic field B and the photon energy on magneto-optical conductivities and Fresnel reflection coefficients. We find that the spin-dependent splittings in graphene exhibit quantized characteristics due to the Landau levels quantization of the magneto-optical conductivities and Fresnel’s reflection coefficients near the Brewster angle. Moreover, the spin-dependent shifts are quantized and show oscillatory behavior with changes in the magnetic field and the photon energy. Our results manifest that the quantized photonic spin-dependent separations are sensitive to variations in the incidence angle, magnetic field, and incident photonic energies. The quantized spin-dependent splitting opens a promising route to find the quantized Hall conductivity and discrete Landau levels in the monolayer graphene by a direct optical weak measurement.

Keywords

• Photonic spin Hall effect
• Landau quantization
• Graphene
• Magneto-optics
• Brewster angle