Quantum spin Hall effect of light

Abstract

Maxwell's equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect, i.e., surface modes with strong spin-momentum locking. These modes are evanescent waves that form, e.g., surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments demonstrating the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell's theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces.

8 pages, 4 figures, Supplementary Materials

References in corpus (13)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Photonics
• Classification of topological insulators and superconductors in three spatial dimensions
• Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
• Dissipationless Quantum Spin Current at Room Temperature
• Chiral nanophotonic waveguide interface based on spin-orbit coupling of light
• Conservation of Angular Momentum, Transverse Shift, and Spin Hall Effect in Reflection and Refraction of Electromagnetic Wave Packet
• Quantum Spin Hall Effect and Topologically Invariant Chern Numbers
• Geometrodynamics of Spinning Light
• Nonlinear surface waves in left-handed materials
• Angular Momenta and Spin-Orbit Interaction of Nonparaxial Light in Free Space
• Nanophotonic control of circular dipole emission: toward a scalable solid-state to flying-qubits interface

Cited by in corpus (7)

• Chiral Quantum Optics
• PTD Symmetry Protected Scattering Anomaly in Optics
• Emergent pseudospin-1 Maxwell fermions with a threefold degeneracy in optical lattices
• Collective polaritonic modes in an array of two-level quantum emitters coupled to optical nanofiber
• The Existence of Topological Edge States in Honeycomb Plasmonic Lattices
• Transverse multipolar light-matter couplings in evanescent waves
• The effects of dissipation on topological mechanical systems