Van der Waals waveguide quantum electrodynamics probed by infrared nano-photoluminescence

TL;DR

This study demonstrates the engineering of van der Waals waveguides using layered 2D materials to modify and enhance the spontaneous emission of embedded quantum emitters, advancing nano-optical quantum electrodynamics applications.

Contribution

It introduces a novel vdW waveguide structure embedding a monolayer MoTe2, enabling direct imaging and quantification of modified emission rates via interferometric nano-photoluminescence.

Findings

Observation of spatially-oscillating emission patterns

Quantification of Purcell enhancement in waveguide modes

Validation of waveguide QED model with experimental data

Abstract

Atomically layered van der Waals (vdW) materials exhibit remarkable properties, including highly-confined infrared waveguide modes and the capacity for infrared emission in the monolayer limit. Here, we engineered structures that leverage both of these nano-optical functionalities. Specifically, we encased a photoluminescing atomic sheet of MoTe2 within two bulk crystals of WSe2, forming a vdW waveguide for the embedded light-emitting monolayer. The modified electromagnetic environment offered by the WSe2 waveguide alters MoTe2 spontaneous emission, a phenomenon we directly image with our interferometric nano-photoluminescence technique. We captured spatially-oscillating nanoscale patterns prompted by spontaneous emission from MoTe2 into waveguide modes of WSe2 slabs. We quantify the resulting Purcell-enhanced emission rate within the framework of a waveguide quantum electrodynamics (QED) model, relating the MoTe2 spontaneous emission rate to the measured waveguide dispersion. Our work marks a significant advance in the implementation of all-vdW QED waveguides.