We embedded an all-hydrocarbon-based carbocation in a metallic microcavity that was tuned to resonance with an electronic transition of the carbocation. The measured Rabi splitting was 41% of the excitation energy, putting the system well into the ultrastrong coupling regime. Importantly, due to the intrinsic charge on the carbocation, the polaritons that form carry a significant charge fraction 0.55e0 and a large charge-to-mass ratio (∼2400e0/m0). Moreover, the ground state of the ultrastrongly coupled system is calculated to carry about one percent of one elementary charge, implying a potentially enhanced charge transport across the molecules. These unique properties of our system, together with its convenient preparation, provide a practical platform to study charged polaritons in the ultrastrong coupling regime.
@article{arxiv.2108.13901,
title = {Organic charged polaritons in the ultrastrong coupling regime},
author = {Mao Wang and Suman Mallick and Anton Frisk Kockum and Karl Börjesson},
journal= {arXiv preprint arXiv:2108.13901},
year = {2022}
}