Customising radiative decay dynamics of two-dimensional excitons via position- and polarisation-dependent vacuum-field interference

TL;DR

This paper introduces a meta-mirror platform that enables precise control of exciton radiative decay dynamics in two-dimensional TMDCs, surpassing traditional methods by offering polarization and position-dependent manipulation.

Contribution

The study presents a novel meta-mirror device that independently controls vacuum-field interference effects on 2D excitons, achieving significant decay rate modulation and polarization-dependent effects.

Findings

Meta-mirror manipulated decay rate by two orders of magnitude.

Identified correlation between emission intensity and spectral linewidth.

Demonstrated polarization-dependent radiative decay control.

Abstract

Embodying bosonic and electrically interactive characteristics in two-dimensional space, excitons in transition-metal dichalcogenides (TMDCs) have garnered considerable attention. The realisation and application of strong-correlation effects, long-range transport, and valley-dependent optoelectronic properties require customising exciton decay dynamics. Strains, defects, and electrostatic doping effectively control the decay dynamics but significantly disturb the intrinsic properties of TMDCs, such as electron band structure and exciton binding energy. Meanwhile, vacuum-field manipulation provides an optical alternative for engineering radiative decay dynamics. Planar mirrors and cavities have been employed to manage the light-matter interactions of two-dimensional excitons. However, the conventional flat platforms cannot customise the radiative decay landscape in the horizontal TMDC plane or independently control vacuum field interference at different pumping and emission frequencies. Here, we present a meta-mirror resolving the issues with more optical freedom. For neutral excitons of the monolayer MoSe2, the meta-mirror manipulated the radiative decay rate by two orders of magnitude, depending on its geometry. Moreover, we experimentally identified the correlation between emission intensity and spectral linewidth. The anisotropic meta-mirror demonstrated polarisation-dependent radiative decay control. We expect that the meta-mirror platform will be promising to tailor the two-dimensional distributions of lifetime, density, and diffusion of TMDC excitons in advanced opto-excitonic applications.