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arXiv · 2204.04041

Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor

M. Wurdack·T. Yun·M. Katzer·A. G. Truscott·A. Knorr·M. Selig·E. A. Ostrovskaya·E. Estrecho
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Abstract

Dispersion engineering is a powerful and versatile tool that can vary the speed of light signals and induce negative-mass effects in the dynamics of particles and quasiparticles. Here, we show that dissipative coupling between bound electron-hole pairs (excitons) and photons in an optical microcavity can lead to the formation of exciton polaritons with an inverted dispersion of the lower polariton branch and hence a negative mass. We perform direct measurements of the anomalous dispersion in atomically thin (monolayer) WS$_2$ crystals embedded in planar microcavities and demonstrate that the propagation direction of the negative-mass polaritons is opposite to their momentum. Our study introduces a new concept of non-Hermitian dispersion engineering for exciton polaritons and opens a pathway for realising new phases of quantum matter in a solid state.

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M. Wurdack, T. Yun, M. Katzer, A. G. Truscott, A. Knorr, M. Selig, E. A. Ostrovskaya, E. Estrecho. 2022-04-08. Negative-mass exciton polaritons induced by dissipative light-matter coupling in an atomically thin semiconductor. https://doi.org/10.1038/s41467-023-36618-6

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