Photonic spin Hall effect on the surface of
anisotropic two-dimensional atomic crystals
WENSHUAI ZHANG,
1
WEIJIE WU,
1
SHIZHEN CHEN,
1
JIN ZHANG,
1
XIAOHUI LING,
1
WEIXING SHU,
2
HAILU LUO,
1,2,
* AND SHUANGCHUN WEN
2
1
Laboratory for Spin Photonics, School of Physics and Electronics, Hunan University, Changsha 410082, China
2
Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education, School of Physics and Electronics,
Hunan University, Changsha 410082, China
*Corresponding author: hailuluo@hnu.edu.cn
Received 28 December 2017; revised 18 March 2018; accepted 18 March 2018; posted 21 March 2018 (Doc. ID 318701);
published 26 April 2018
We examine the spin-orbit interaction of light and photonic spin Hall effect on the surface of anisotropic two-
dimensional atomic crystals. As an example, the photonic spin Hall effect on the surface of black phosphorus is
investigated. The photonic spin Hall effect manifests itself as the spin-dependent beam shifts in both transverse
and in-plane directions. We demonstrate that the spin-dependent shifts are sensitive to the orientation of the
optical axis, doping concentration, and interband transitions. These results can be extensively extended to other
anisotropic two-dimensional atomic crystals. By incorporating the quantum weak measurement techniques, the
photonic spin Hall effect holds great promise for detecting the parameters of anisotropic two-dimensional atomic
crystals.
© 2018 Chinese Laser Press
OCIS codes: (260.5430) Polarization; (260.2110) Electromagnetic optics.
https://doi.org/10.1364/PRJ.6.000511
1. INTRODUCTION
Two-dimensional (2D) atomic crystals hold great promise in
the application of optoelectronics due to their extraordinary
electronic and photonic properties [1,2]. Therefore, a funda-
mental understanding of the light-matter interaction is essential
to optoelectronics applications. The photonic spin Hall effect
(SHE) manifesting itself as spin-dependent splitting in the
light-matter interaction is considered as a result of the spin-
orbit interaction of light [3,4]. The photonic SHE can be
regarded as a direct photonic analogy of electronic SHE,
which has been extensively studied in 3D bulk crystal [5,6].
The spin-dependent splitting in photonic SHE is generally
on subwavelength scales, which can be observed by the signal
enhancement technique known as quantum weak measure-
ments [7,8].
More recently, the spin-orbit interaction of light and pho-
tonic SHE has been investigated on the surface of 2D atomic
crystals. In general, the interpretation of reflection and refrac-
tion on the surface of 2D atomically thin crystals is treated as a
homogeneous medi um with an effective refractive index and an
effective thickness. However, it is not necessary to involve the
effective refractive index to describe the light-matter interaction
[9–11] and spin-orbit interaction [12] on the surface of
atomically thin crystals. The quantized Imbert–Fedorov
effect and Goos–Hänchen effect have been theoretically
predicted in the quantum Hall regime of graphene-substrate
systems [13,14]. Photonic Hall shifts are sensitive to spin-
and-valley properties of the charge carriers, providing an
unprecedented pathway to investigate spintronics and valley-
tronics [15]. The beam shifts on the surface of graphene have
been observed via weak measurements [16,17]. In addition, the
strong spin-orbit interaction and giant spin-dependent
shifts on the surface of graphene have also been predicted
[18,19].
Anisotropic 2D atomic crystals provide an extra degree of
freedom to tailor the light-matter interaction due to the strong
anisotropy [20]. Motivated by the interesting properties, we
attempt to examine the spin-orbit interaction of light and pho-
tonic SHE on the surface of anisotropic 2D atomic crystals.
Black phosphorus, an elemental layered material composed
of layers of atoms, has an atomic structure that resembles gra-
phene. But the atomic rings in black-phosphorus layers exhibit
a puckered structure, which makes it have strong anisotropic
properties [21]. In this paper, a general model is developed
to describe the photonic SHE in reflection on the surface of
anisotropic 2D atomic crystals. Based on this model, both
transverse and in-plane spin-dependent splitting in photonic
SHE can be obtained. We demonstrate that the spin-
dependent shifts are sensitive to the orientation of the optical
axis, doping concentration, and interband transitions.
Research Art icle
Vol. 6, No. 6 / June 2018 / Photonics Research 511
2327-9125/18/060511-06 Journal © 2018 Chinese Laser Press