Nonlinear non-Hermitian higher-order topological laser

TL;DR

This paper explores topological lasers combining nonlinear, non-Hermitian, and topological lattice systems, demonstrating stable lasing at edges or corners initiated by site stimulation, with potential for observable topological state profiles.

Contribution

It introduces a novel approach to topological lasing using quench dynamics in nonlinear non-Hermitian topological lattices, highlighting stable lasing and state profile observability.

Findings

Stable lasing occurs at topological edges or corners after site stimulation.

Lasing profiles reveal topological edge or corner states.

Non-Hermitian gain and loss are crucial for lasing stability.

Abstract

We investigate topological lasers in combination of nonlinear, non-Hermitian and topological lattice systems based on a quench dynamics starting from one site. We consider explicitly the topological laser in the Su-Schrieffer-Heeger (SSH) model with two topological edge states and the second-order topological laser in the breathing Kagome lattice with three topological corner states. Once we stimulate any one site, after a delay, all sites belonging to the topological edge or corner states begin to emit stable laser light depending on the density of states, although no wave propagation is observed from the stimulated site. It is intriguing that the profile of topological edge or corner states is observable by measuring the intensity of lasing. The phenomenon occurs due to a combinational effect of linear non-Hermitian loss terms and nonlinear non-Hermitian gain terms in the presence of the topological edge or corner states.