Abstract
Light emitters in the vicinity of a hyperbolic metamaterial (HMM) show a range of quantum optical phenomena from spontaneous decay-rate enhancement to strong coupling. In this study, we integrate a monolayer molybdenum disulfide () emitter in the near-field region of the HMM. The monolayer has and excitons, which emit in the red region of the visible spectrum. We find that the excitons couple to the HMM differently compared to excitons. The fabricated HMM transforms to a hyperbolic dispersive medium at 2.14 eV, from an elliptical dispersive medium. The selective coupling of excitons to the HMM modes is attributed to the inbuilt field gradient of the transition. The exciton energy lies close to the transition point of the HMM, relative to the exciton. So, the HMM modes couple more to the excitons and the metamaterial functions as a selective coupler. The coupling strength calculations show that coupling is 2.5 times stronger for excitons relative to excitons. High near field of HMM, large magnitude, and the in-plane transition dipole moment of excitons, result in strong coupling of excitons and formation of hybrid light-matter states. The measured differential reflection and photoluminescence spectra indicate the presence of hybrid light-matter states, i.e., exciton polaritons. Rabi splitting of meV at room temperature is observed. The low-temperature photoluminescence measurement shows mode anticrossing, which is a characteristic feature of hybrid states. Our results show that the HMM works as an energy-selective coupler for multiexcitonic systems as .
- Received 18 January 2022
- Revised 4 April 2022
- Accepted 12 May 2022
DOI:https://doi.org/10.1103/PhysRevApplied.18.014004
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