Interacting polariton fluids in a monolayer of tungsten disulfide

TL;DR

This paper demonstrates that monolayer tungsten disulfide can support Bloch surface wave polaritons with strong nonlinearities, enabling potential applications in integrated optical processing and polaritonic circuits at room temperature.

Contribution

It is the first to show strong polariton nonlinearities in TMD monolayers and demonstrates their use in a nonlinear polariton source.

Findings

Achieved Rabi splitting of 43 meV in WS2 monolayer BSWPs

Observed reversible blueshift of 12.9 meV indicating strong nonlinearities

Demonstrated long-range propagation of BSWPs in TMDs

Abstract

Atomically thin transition metal dichalcogenides (TMDs) possess a number of properties that make them attractive for realizing room-temperature polariton devices. An ideal platform for manipulating polariton fluids within monolayer TMDs is that of Bloch surface waves, which confine the electric field to a small volume near the surface of a dielectric mirror. Here we demonstrate that monolayer tungsten disulfide ($\text{WS}_2$) can sustain Bloch surface wave polaritons (BSWPs) with a Rabi splitting of 43 meV and propagation constants reaching 33 $\mu$m. In addition, we evidence strong polariton-polariton nonlinearities within BSWPs, which manifest themselves as a reversible blueshift of the lower polariton resonance by up to 12.9$\pm$0.5 meV. Such nonlinearities are at the heart of polariton devices and have not yet been demonstrated in TMD polaritons. As a proof of concept, we use the nonlinearity to implement a nonlinear polariton source. Our results demonstrate that BSWPs using TMDs can support long-range propagation combined with strong nonlinearities, enabling potential applications in integrated optical processing and polaritonic circuits.