Robustness and observability of rotating vortex-lattices in an exciton-polariton condensate

TL;DR

This paper investigates the stability of vortex lattices in exciton-polariton condensates under real-world imperfections and proposes an interference-imaging method for their experimental detection.

Contribution

It analyzes how disorder and potential deformations affect vortex lattice stability and introduces a practical imaging technique for observing these structures.

Findings

Vortex lattices are robust against certain levels of disorder.

Deformations of the trapping potential can destabilize vortex arrangements.

A feasible interference-imaging scheme is proposed for experimental detection.

Abstract

Exciton-polariton condensates display a variety of intriguing pattern-forming behaviors, particularly when confined in potential traps. It has previously been predicted that triangular lattices of vortices of the same sign will form spontaneously as the result of surface instabilities in a harmonic trap. However, natural disorder, deviation of the external potential from circular symmetry, or higher-order terms modifying the dynamical equations may all have detrimental effects and destabilize the circular trajectories of vortices. Here we address these issues, by characterizing the robustness of the vortex lattice against disorder and deformations of the trapping potential. Since most experiments use time integrated measurements it would be hard to observe directly the rotating vortex lattices or distinguish them from vortex-free states. We suggest how these difficulties can be overcome and present an experimentally viable interference-imaging scheme that would allow the detection of rotating vortex lattices.