Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature

TL;DR

This paper demonstrates room-temperature strong coupling between multilayer WSe2 and plasmonic nanocavities, achieving significant Rabi splittings and enhanced nonlinear exciton functionalities with high quantum efficiency.

Contribution

It shows that strong coupling is feasible with multilayer WSe2 in compact gold nanocavities, overcoming limitations with monolayers, and provides experimental evidence of anti-crossings and high Rabi splittings.

Findings

Strong coupling achieved with 8-layer WSe2 in gold nanocavities.

Rabi splitting exceeds 135 meV.

Nonlinear exciton functionalities enhanced by at least 10^4.

Abstract

Strong-coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact robust easily-assembled gold nano-gap resonators at room temperature. We prove that strong coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for 8 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10^4, while retaining quantum efficiencies above 50%.