Floquet topological insulator laser

TL;DR

This paper presents a novel topological laser system based on Floquet topological insulators, utilizing twisted waveguide arrays to achieve stable, robust lasing in topological edge states with potential resilience to defects.

Contribution

It introduces a new class of topological lasers using photonic Floquet insulators with twisted waveguides, demonstrating stable topological edge lasing and robustness against lattice defects.

Findings

Lasing occurs in topological edge states with stable dynamics.

Topological robustness is confirmed through defect simulations.

Lasing stability depends on specific Bloch momentum intervals.

Abstract

We introduce a class of topological lasers based on the photonic Floquet topological insulator concept. The proposed system is realized as a truncated array of the lasing helical waveguides, where the pseudo-magnetic field arises due to twisting of the waveguides along the propagation direction that breaks the time-reversal symmetry and opens up a topological gap. When sufficient gain is provided in the edge channels of the array then the system lases into the topological edge states. Topological lasing is stable only in certain intervals of the Bloch momenta, that ensure a dynamic, but stable balance between the linear amplification and nonlinear absorption leading to the formation of the breathing edge states. We also illustrate topological robustness of the edge currents by simulating lattice defects and triangular arrangements of the waveguides.