A single quantum dot (QD) strongly coupled with a plasmonic nanoparticle yields a promising qubit for scalable solid-state quantum information processing at room temperature. However, realizing such a strong coupling remains challenging due to the difficulty of spatial overlap of the QD excitons with the plasmonic electric fields (EFs). In this work, Prof. Renming Liu cooperating with Xue-Hua Wang’s research group demonstrate for the first time that this overlap can be overcome by integrating a deterministic single QD with a single Au nanorod. When a wedge nanogap cavity consisting of them and the substrate is constructed, the plasmonic EFs can be more effectively “dragged” and highly confined in the QD’s nanoshell where the excitons mainly reside. With these advantages, we observed the largest spectral Rabi splitting (reported so far) of ∼234 meV for a single QD strong coupling with plasmons. This work opens a pathway to the massive construction of room-temperature strong coupling solid qubits.

The related paper entitled with "Room-Temperature Strong Coupling Between a Single Quantum Dot and a Single Plasmonic Nanoparticle" has been published in Nano Letters. Drs. Jun-Yu Li and Wei Li are the co-first authors, Prof. Renming Liu and Prof. Xue-Hua Wang are the corresponding authors. The research work is supported by the National Key R&D Program of China, the National Natural Science Foundations of China, the Key-Area Research and Development Program of Guangdong Province, the Guangdong Special Support Program, and Henan University.

Link to this paper: https://pubs.acs.org/doi/abs/10.1021/acs.nanolett.2c00606