Engineering spin-orbit coupling for photons and polaritons in microstructures

Abstract

One of the most fundamental properties of electromagnetism and special relativity is the coupling between the spin of an electron and its orbital motion. This is at the origin of the fine structure in atoms, the spin Hall effect in semiconductors, and underlies many intriguing properties of topological insulators, in particular their chiral edge states. Configurations where neutral particles experience an effective spin-orbit coupling have been recently proposed and realized using ultracold atoms and photons. Here we use coupled micropillars etched out of a semiconductor microcavity to engineer a spin-orbit Hamiltonian for photons and polaritons in a microstructure. The coupling between the spin and orbital momentum arises from the polarisation dependent confinement and tunnelling of photons between micropillars arranged in the form of a hexagonal photonic molecule. Dramatic consequences of the spin-orbit coupling are experimentally observed in these structures in the wavefunction of polariton condensates, whose helical shape is directly visible in the spatially resolved polarisation patterns of the emitted light. The strong optical nonlinearity of polariton systems suggests exciting perspectives for using quantum fluids of polaritons11 for quantum simulation of the interplay between interactions and spin-orbit coupling.

main text: pages 1-11 (4 figures); supplementary material: pages 12-28 (9 figures)

References in corpus (9)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Quantum fluids of light
• Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
• Emergence of the persistent spin helix in semiconductor quantum wells
• Photon blockade induced Mott transitions and XY spin models in coupled cavity arrays
• Polariton laser using single micropillar GaAs-GaAlAs semiconductor cavities
• Spatial and spectral shape of inhomogeneous non-equilibrium exciton-polariton condensates
• Half-solitons in a polariton quantum fluid behave like magnetic monopoles
• Spin-orbit coupling and optical spin Hall effect in photonic graphene

Cited by in corpus (4)

• Topological Photonics
• Polariton $\mathbb{Z}$ Topological Insulator
• Photonic Versus Electronic Quantum Anomalous Hall Effect
• Elastic Spin Hall effect in Mechanical Graphene