Collective excitations of exciton-polariton condensates in a synthetic gauge field

TL;DR

This paper experimentally investigates the anisotropic collective excitations of exciton-polariton condensates in microcavities with synthetic gauge fields, revealing spin-dependent interactions and textures.

Contribution

It provides the first direct measurement of excitation dispersions in spinor polariton condensates under synthetic gauge fields, confirming theoretical predictions.

Findings

Observed anisotropic excitation dispersions matching theory

Extracted inter- and intra-spin polariton interaction constants

Mapped spin textures in the condensate

Abstract

Collective (elementary) excitations of quantum bosonic condensates, including condensates of exciton polaritons in semiconductor microcavities, are a sensitive probe of interparticle interactions. In anisotropic microcavities with momentum-dependent TE-TM splitting of the optical modes, the excitations dispersions are predicted to be strongly anisotropic, which is a consequence of the synthetic magnetic gauge field of the cavity, as well as the interplay between different interaction strengths for polaritons in the singlet and triplet spin configurations. Here, by directly measuring the dispersion of the collective excitations in a high-density optically trapped exciton-polariton condensate, we observe excellent agreement with the theoretical predictions for spinor polariton excitations. We extract the inter- and intra-spin polariton interaction constants and map out the characteristic spin textures in an interacting spinor condensate of exciton polaritons.