Photonic spin Hall effect in topological insulators

Abstract

In this paper we theoretically investigate the photonic spin Hall effect (SHE) of a Gaussian beam reflected from the interface between air and topological insulators (TIs). The photonic SHE is attributed to spin-orbit coupling and manifests itself as in-plane and transverse spin-dependent splitting. We reveal that the spin-orbit coupling effect in TIs can be routed by adjusting the axion angle variations. Unlike the transverse spin-dependent splitting, we find that the in-plane one is sensitive to the axion angle. It is shown that the polarization structure in magneto-optical Kerr effect is significantly altered due to the spin-dependent splitting in photonic SHE. We theoretically propose a weak measurement method to determine the strength of axion coupling by probing the in-plane splitting of photonic SHE.

Topological Phase Transitions in the Photonic Spin Hall Effect

“…Previous studies on SHEL in the graphene family have been restricted to graphene [27][28][29], therefore overlooking the role of finite staggering, spin-orbit coupling, and spin/valley dynamics. The interplay between topological matter and SHEL was considered in magnetic field biased bulk materials with axion coupling [30]. In this letter we take advantage of the crossroads between topology, phase transitions, spin-orbit interactions, and Dirac physics in staggered 2D semiconductors to uncover magnetic field free topological phase transitions in the photonic spin Hall effect.…”

Strong spin-orbit interaction of light on the surface of atomically thin crystals

“…The photonic SHE can be regarded as a direct optical analogy of the SHE in electronic systems [17][18][19][20][21] where the spin electrons and electric potential are replaced by spin photons and a refractive index gradient, respectively. The analogy has been extensively demonstrated effective for the photonic SHE in 3D bulk crystals [22][23][24][25][26][27][28][29][30]. However, the effective refractive index fails to adequately explain the light-matter interaction in 2D atomic crystals.…”

Quantized beam shifts in graphene

“…In this case spatial and angular deviations from the expected ray trajectories occur, resulting in beam shifts within and transverse to the incidence plane, respectively called Goos-Hänchen (GH) [2] and Imbert-Fedorov (IF) [3,4] shifts. Even though the spatial IF shift vanishes for transverse electric or transverse magnetic linearly polarized light, photons with opposite heliticities are still shifted to distinct edges of the reflected/transmitted beam cross section -the spin Hall effect of light (SHEL) [5][6][7][8][9]. These shifts are relevant for biosensing [10] and nano-probing [11], and have been studied for a variety of beam profiles and material media [12][13][14][15][16][17][18][19][20][21].…”