Strong coupling between excitons in transition metal dichalcogenides and optical bound states in the continuum

TL;DR

This paper demonstrates strong coupling between optical bound states in the continuum and excitons in monolayer transition metal dichalcogenides, significantly enhancing exciton-polariton lifetimes and enabling new polaritonic device applications.

Contribution

It introduces a method to engineer exciton-polariton lifetimes using BICs in photonic structures, allowing control over hybrid states across momentum space.

Findings

Giant radiative lifetime of BICs enhances exciton-polariton lifetime by three orders of magnitude.

Maximal hybrid state lifetime can be achieved at any momentum by structure shaping.

Potential for creating moving exciton-polariton condensates without Bragg mirrors.

Abstract

Being motivated by recent achievements in the rapidly developing fields of optical bound states in the continuum (BICs) and excitons in monolayers of transition metal dichalcogenides, we analyze strong coupling between BICs in $\rm Ta_2O_5$ periodic photonic structures and excitons in $\rm WSe_2$ monolayers. We demonstrate that giant radiative lifetime of BICs allow to engineer the exciton-polariton lifetime enhancing it three orders of magnitude compared to a bare exciton. We show that maximal lifetime of hybrid light-matter state can be achieved at any point of $\mathbf{k}$-space by shaping the geometry of the photonic structure. Our findings open new route for the realization of the moving exciton-polariton condensates with non-resonant pump and without the Bragg mirrors which is of paramount importance for polaritonic devices.