Motional narrowing, ballistic transport, and trapping of room-temperature exciton polaritons in an atomically-thin semiconductor

Abstract

Atomically-thin transition metal dichalcogenide crystals (TMDCs) hold great promise for future semiconductor optoelectronics due to their unique electronic and optical properties. In particular, electron-hole pairs (excitons) in TMDCs are stable at room temperature and interact strongly with light. When TMDCs are embedded in an optical microcavity, the excitons can hybridise with cavity photons to form exciton polaritons (polaritons herein), which display both ultrafast velocities and strong interactions. The ability to manipulate and trap polaritons on a microchip is critical for future applications. Here, we create a potential landscape for room-temperature polaritons in monolayer WS${}_2$, and demonstrate their free propagation and trapping. We show that the effect of dielectric disorder, which restricts the diffusion of WS${}_2$ excitons and broadens their spectral resonance, is dramatically reduced in the strong exciton-photon coupling regime leading to motional narrowing. This enables the ballistic transport of WS${}_2$ polaritons across tens of micrometers with an extended range of partial first-order coherence. Moreover, the dephasing of trapped polaritons is dramatically suppressed compared to both WS${}_2$ excitons and free polaritons. Our results demonstrate the possibility of long-range transport and efficient trapping of TMDC polaritons in ambient conditions.

8 pages, 4 figures

References in corpus (9)

• Strong light-matter coupling in two-dimensional atomic crystals
• Observation of Superfluidity of Polaritons in Semiconductor Microcavities
• Exciton-polariton condensates
• Exciton-exciton interaction in transition-metal dichalcogenide monolayers
• Energy Relaxation in a 1-D Polariton Condensate
• Stochastic Gross-Pitaevskii Equation for the Dynamical Thermalization of Bose-Einstein Condensates
• First-order spatial coherence measurements in a thermalized two-dimensional photonic quantum gas
• Influence of direct deposition of dielectric materials on the optical response of monolayer WS${}_2$
• Giant increase of temporal coherence in optically trapped polariton condensate

Cited by in corpus (10)

• Unveiling the mixed nature of polaritonic transport: From enhanced diffusion to ballistic motion approaching the speed of light
• Ultrafast imaging of polariton propagation and interactions
• Enhanced Excitation Energy Transfer under Strong Light-Matter Coupling: Insights from Multi-Scale Molecular Dynamics Simulations
• Spatial coherence of room-temperature monolayer WSe${}_2$ exciton-polaritons in a trap
• Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor
• Brightening of a dark monolayer semiconductor via strong light-matter coupling in a cavity
• Enhancing ground state population and macroscopic coherence of room-temperature WS${}_2$ polaritons through engineered confinement
• Microscopic modelling of exciton-polariton diffusion coefficients in atomically thin semiconductors
• Coherent Dynamics of Floquet-Bloch States in Monolayer WS2 Reveals Fast Adiabatic Switching
• Fabrication of high-quality PMMA/SiO${}_x$ spaced planar microcavities for strong coupling of light with monolayer WS${}_2$ excitons