Exciton-polaritons in van der Waals heterostructures embedded in tunable microcavities

TL;DR

This paper demonstrates strong light-matter coupling in van der Waals heterostructures with MoSe2 quantum wells embedded in tunable microcavities, revealing exciton-polariton states with potential for room-temperature polaritonic devices.

Contribution

It reports the first observation of exciton-polaritons in VDW heterostructures with tunable microcavities, showing enhanced coupling and potential for optoelectronic applications.

Findings

Observation of exciton-polaritons with 20-29 meV splitting

Estimated exciton radiative lifetime of 0.4 ps

Potential for room-temperature polaritonic devices

Abstract

Layered materials can be assembled vertically to fabricate a new class of van der Waals (VDW) heterostructures a few atomic layers thick, compatible with a wide range of substrates and optoelectronic device geometries, enabling new strategies for control of light-matter coupling. Here, we incorporate molybdenum diselenide/boron nitride (MoSe$_2$/hBN) quantum wells (QWs) in a tunable optical microcavity. Part-light-part-matter polariton eigenstates are observed as a result of the strong coupling between MoSe$_2$ excitons and cavity photons, evidenced from a clear anticrossing between the neutral exciton and the cavity modes with a splitting of 20 meV for a single MoSe$_2$ monolayer QW, enhanced to 29 meV in MoSe$_2$/hBN/MoSe$_2$ double-QWs. The splitting at resonance provides an estimate of the exciton radiative lifetime of 0.4 ps. Our results pave the way for room temperature polaritonic devices based on multiple-QW VDW heterostructures, where polariton condensation and electrical polariton injection through the incorporation of graphene contacts may be realised.