Optical analogue of Dresselhaus spin-orbit interaction in photonic graphene

TL;DR

This paper demonstrates the experimental creation of a synthetic non-Abelian gauge field for photons in a honeycomb microcavity lattice, revealing Dresselhaus spin-orbit interaction effects and enabling potential on-chip photon manipulation.

Contribution

It reports the first experimental realization of a non-Abelian gauge field for light, showing Dresselhaus spin-orbit interaction in photonic graphene and its optical consequences.

Findings

Observation of optical spin Hall effect indicating spin precession.

Detection of Dresselhaus symmetry in the gauge field.

Sign reversal of the field between s and p bands.

Abstract

The concept of gauge fields plays a significant role in many areas of physics from particle physics and cosmology to condensed matter systems, where gauge potentials are a natural consequence of electromagnetic fields acting on charged particles and are of central importance in topological states of matter. Here, we report on the experimental realization of a synthetic non-Abelian gauge field for photons in a honeycomb microcavity lattice. We show that the effective magnetic field associated with TE-TM splitting has the symmetry of Dresselhaus spin-orbit interaction around Dirac points in the dispersion, and can be regarded as an SU(2) gauge field. The symmetry of the field is revealed in the optical spin Hall effect (OSHE), where under resonant excitation of the Dirac points precession of the photon pseudospin around the field direction leads to the formation of two spin domains. Furthermore, we observe that the Dresselhaus field changes its sign in the same Dirac valley on switching from s to p bands in good agreement with the tight binding modelling. Our work demonstrating a non-Abelian gauge field for light on the microscale paves the way towards manipulation of photons via spin on a chip.