Enhancement of photonic spin Hall effect in grating waveguide structure with Weyl semimetal layer

Abstract The photonic spin Hall effect manifests as spin-dependent transverse displacements of light, offering potential for applications in polarization-sensitive optics and quantum sensing. This work introduces an innovative design that amplifies the photonic spin Hall effect by incorporating a Weyl semimetal layer into a grating waveguide structure. Due to the anisotropic dielectric tensor and intrinsic nonreciprocal optical behavior, Weyl semimetals are capable of significantly enhancing spin-dependent light shifts. By examining the light–matter interaction within the proposal, we reveal a modulation of spin–orbit coupling that amplifies spin Hall shifts. The structural parameters of the design are further optimized, providing a tunable platform for controlling the spin Hall effect response across a broad range of wavelengths. Numerical simulations reveal a substantial enhancement of the photonic spin Hall effect, outperforming conventional guided mode resonance systems. This enhancement opens new avenues for the development of nonreciprocal photonic devices, including spin-controlled modulators and optical isolators.