Tunable two-dimensional laser arrays with zero-phase locking

TL;DR

This paper demonstrates a method to create large-scale, tunable 2D laser arrays by combining higher-order topological insulator physics with the non-Hermitian skin effect, enabling stable, single-mode, zero-phase locked lasing across the array.

Contribution

It introduces a novel approach to engineer 2D laser arrays with tunable power and phase locking using topological and non-Hermitian effects, supported by computational and experimental platform proposals.

Findings

Stable, single-mode lasing with zero phase difference.

Lasing power proportional to the lattice area.

Proposed platform using coupled optical ring resonators.

Abstract

Two-dimensional (2D) laser arrays are shown to be achievable at a large scale by exploiting the interplay of higher-order topological insulator (HOTI) physics and the so-called non-Hermitian skin effect (NHSE). The higher-order topology allows for the amplification and hence lasing of a single-mode protected by a band gap; whereas the NHSE, widely known to accumulate population in a biased direction in non-Hermitian systems, is introduced to compete with the topological localization of corner modes. By tuning the system parameters appropriately and pumping at one site only, a single topologically protected lasing mode delocalized across over two dimensions emerges, with its power widely tunable by adjusting the pump strength. Computational studies clearly indicate that the lasing mode thus engineered is stable, and the phase difference between nearest lasing sites is locked at zero, even after the disorder is accounted for. The total power of the lasing mode forming a 2D topological laser array is proportional to the area of the 2D lattice accommodating a HOTI phase. Based on existing experiments, we further propose to use coupled optical ring resonators as a promising platform to realize large-scale 2D laser arrays.