Spin-Orbit Coupling for Photons and Polaritons in Microstructures

V G Sala,A Nalitov,E Galopin,I Carusotto,J Bloch,T Jacqmin,D D Solnyshkov,A Amo,G Malpuech,H Terças,M Abbarchi,A Lemaître,I Sagnes

doi:10.1103/physrevx.5.011034

Abstract

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 polarization-dependent confinement and tunneling of photons between adjacent micropillars arranged in the form of a hexagonal photonic molecule. It results in polariton eigenstates with distinct polarization patterns, which are revealed in photoluminescence experiments in the regime of polariton condensation. Thanks to the strong polariton nonlinearities, our system provides a photonic workbench for the quantum simulation of the interplay between interactions and spin-orbit effects, particularly when extended to two-dimensional lattices.Received 23 October 2014DOI:https://doi.org/10.1103/PhysRevX.5.011034This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical Society

Highlights

Spin-orbit (SO) coupling is the coupling between the motion and spin of a particle
As the broad linewidth of the emission under a weak incoherent pump does not allow resolving the spin-orbit split states, we study the emission under a stronger pump: Polariton condensation occurs [39] and the emission linewidth is dramatically reduced
The polarization patterns associated with the spin-orbit coupled states depicted in Figs. 2(f) and 2(g) can be evidenced at high excitation density, when polariton condensation takes place and the population ends up accumulating in a single quantum state with a reduced linewidth [39]

Summary

INTRODUCTION

Spin-orbit (SO) coupling is the coupling between the motion and spin of a particle. It gives rise to the fine structure in atomic spectra, and it is naturally present in some bulk materials. In combination with the strong spin-dependent interactions naturally present in microcavity-polariton devices and the possibility of scaling up to lattices of arbitrary geometry [16,17,18], the realization of such a coupling in semiconductor microcavities would open the way to the simulation of many-body effects in a new quantum optical context [19]. We report on the engineering of the coupling between the polarization (spin) and the momentum (orbital) degrees of freedom of polaritons using a photonic microstructure with a ringlike shape. Photons are strongly coupled to quantum-well excitons, giving rise to polariton states, which hold the same polarization properties of the confined photons. We show that the engineered SO coupling drives the condensation of polaritons into states with complex spin textures

HEXAGONAL PHOTONIC MOLECULE

LOW POWER

EMERGENCE OF THE SPIN-ORBIT COUPLING

HIGH-POWER EXPERIMENTS

CONCLUSIONS