Modulational instability and solitary waves in polariton topological insulators

TL;DR

This paper predicts the emergence of robust, localized topological quasi-solitons in nonlinear polariton topological insulators, extending the understanding of edge state instabilities beyond the linear regime.

Contribution

It introduces the prediction of nonlinear instabilities leading to topological quasi-solitons in polariton topological insulators, a novel insight into their nonlinear dynamics.

Findings

Nonlinear instabilities of topological edge states are predicted.

Formation of topological quasi-solitons that are robust and immune to backscattering.

Results set the stage for experimental studies of nonlinear polariton topological insulators.

Abstract

Optical microcavities supporting exciton-polariton quasi-particles offer one of the most powerful platforms for investigation of rapidly developing area of topological photonics in general, and of photonic topological insulators in particular. Energy bands of the microcavity polariton graphene are readily controlled by magnetic field and influenced by the spin-orbit coupling effects, a combination leading to formation of linear unidirectional edge states in polariton topological insulators as predicted very recently. In this work we depart from the linear limit of non-interacting polaritons and predict instabilities of the nonlinear topological edge states resulting in formation of the localized topological quasi-solitons, which are exceptionally robust and immune to backscattering wavepackets propagating along the graphene lattice edge. Our results provide a background for experimental studies of nonlinear polariton topological insulators and can influence other subareas of photonics and condensed matter physics, where nonlinearities and spin-orbit effects are often important and utilized for applications.