Enhanced Strong Coupling between Spin Ensemble and non-Hermitian Topological Edge States

TL;DR

This paper demonstrates enhanced strong coupling between topological edge states in a non-Hermitian photonic lattice and a spin ensemble, revealing new ways to engineer robust light-matter interactions using topological and non-Hermitian principles.

Contribution

It introduces a parity-time-symmetric photonic lattice to generate complex edge states and enhances light-matter coupling, combining topological protection with non-Hermitian engineering.

Findings

Enhanced strong coupling between photonic edge states and magnon modes.

Generation of complex-valued edge states via PT-symmetry breaking.

Strategies for engineering topological light-matter interactions.

Abstract

Light-matter interaction is crucial to both understanding fundamental phenomena and developing versatile applications. Strong coupling, robustness, and controllability are the three most important aspects in realizing light-matter interactions. Topological and non-Hermitian photonics, have provided frameworks for robustness and extensive control freedom, respectively. How to engineer the properties of the edge state such as photonic density of state, scattering parameters by using non-Hermitian engineering while ensuring topological protection has not been fully studied. Here we construct a parity-time-symmetric dimerized photonic lattice and generate complex-valued edge states via spontaneous PT-symmetry breaking. The enhanced strong coupling between the topological photonic edge mode and magnon mode in a ferromagnetic spin ensemble is demonstrated. Our research reveals the subtle non-Hermitian topological edge states and provides strategies for realizing and engineering topological light-matter interactions.