Photonic spin Hall effect of monolayer black phosphorus in the Terahertz region

Abstract

As a two-dimensional (2D) material, black phosphorus (BP) has attracted significant attention owing to exotic physical properties such as low-energy band gap, high carrier mobility, and strong in-plane anisotropy. The striking in-plane anisotropy is a promising candidate for novel light-matter interaction. Here, we investigate the photonic spin Hall effect (PSHE) on a monolayer of BP. Due to the in-plane anisotropic property of BP, the PSHE is accompanied with Goos-Hänchen and Imbert-Fedorov effects, resulting in an asymmetric spin splitting. The asymmetric spin splitting can be flexibly tuned by the angle between the incident plane and the armchair crystalline direction of BP and by the carrier density via a bias voltage. The centroid displacements of two opposite spin components of the reflected beam along directions parallel and perpendicular to the incident plane can be considered as four independent channels for information processing. The potential application in barcode-encryption is proposed and discussed. These findings provide a deeper insight into the spin-orbit interaction in 2D material and thereby facilitate the development of optoelectronic devices in the Terahertz region.

Structural Design and Pyroelectric Property of SnS/CdS Heterojunctions Contrived for Low‐Temperature Visible Photodetectors

“…[ 1–6 ] They work based on the photoelectric effect by virtue of strong light absorption capability and high photoelectric conversion efficiency of these semiconductors. [ 7,8 ] However, in cryogenic detection environment including deep space and polar exploration, the traditional visible photodetectors based on photoelectric effect exhibit inferior response or even out of operation. This is because the band gaps of semiconductors increase with decreasing temperature, [ 9 ] and the excitation probability of carriers is dramatically reduced at low temperatures, leading to a weak photoelectric efficiency.…”

Tunable plasmon-phonon polaritons in anisotropic 2D materials on hexagonal boron nitride

“…Such anisotropic 2D materials (A2DMs) includes the group V mono-and multilayers, most notably black phosphorus (BP) [19,20]. BP is a multilayer plasmonic A2DM with actively tunable electronic and optical properties [21], and thus has found numerous applications in optoelectronics and plasmonics [6,7,[9][10][11][22][23][24][25][26][27][28][29][30]. SPPs confined to plasmonic metasurfaces or A2DMs exhibit a hyperbolic or figure-eight-like dispersion.…”

Limitations of the transmitted photonic spin Hall effect through layered structure

“…In recent years, numerous measures focusing on various resonant structural designs to enhance the photonic SHE have been proposed, including surface plasmon resonance (SPR) 7 and long range SPR excitation structures 8 , photon tunneling 9 and resonant optical tunneling effect (ROTE) structures 10 , frustrating total internal reflection (FTIR) structures 11 , bound states in the continuum (BICs) structures 12 , graphene/MoS 2 heterostructures 13 , metasurfaces 14 , etc. On the other hand, various unconventional materials have also been proposed to enhance the SHE, including epsilon-near-zero (ENZ) materials 15 , anisotropic ENZ 16 and lossy ENZ 17 , hyperbolic metamaterials 18,19 , anisotropic metamaterials 20 , graphene [21][22][23] and black phosphorus 24 , polymers 25 , topological insulators 26 , and so on. So far, a few investigations have shown dramatic spin-dependent transverse displacements.…”