All-optical control of the quantum flow of a polariton superfluid

TL;DR

This paper demonstrates the all-optical control of vortex-antivortex pairs in a polariton superfluid flowing against an artificial potential barrier, revealing new ways to manipulate quantum fluid dynamics using light.

Contribution

It introduces a method to control and trap vortices in a polariton superfluid via tailored optical beams, extending theoretical predictions with experimental validation.

Findings

Vortex-antivortex pairs form in polariton condensates flowing against barriers.

The initial vortex trajectories depend on barrier strength and size.

Optical beams can permanently trap and store vortices.

Abstract

While photons in vacuum are massless particles that do not interact with each other, significant photon-photon interactions appear in suitable nonlinear media, leading to novel hydrodynamic behaviors typical of quantum fluids. Here we show the formation of vortex-antivortex pairs in a Bose-Einstein condensate of exciton-polaritons -a coherent gas of strongly dressed photons- flowing at supersonic speed against an artificial potential barrier created and controlled by a light beam in a planar semiconductor microcavity. The observed hydrodynamical phenomenology is in agreement with original theoretical predictions based on the Gross-Pitaevskii equation, recently generalized to the polariton context. However, in contrast to this theoretical work, we show how the initial position and the subsequent trajectory of the vortices crucially depend on the strength and size of the artificial barrier. Additionally, we demonstrate how a suitably tailored optical beam can be used to permanently trap and store the vortices that are hydrodynamically created in the wake of a natural defect. These observations are borne out by time-dependent theoretical simulations.