Qin Jian, Chen Yu-Hui, Zhang Zhepeng, Zhang Yanfeng, Blaikie Richard J, Ding Boyang, Qiu Min
State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
School of Physics, Beijing Institute of Technology, Beijing 10081, People's Republic of China.
Phys Rev Lett. 2020 Feb 14;124(6):063902. doi: 10.1103/PhysRevLett.124.063902.
Strong coupling of two-dimensional semiconductor excitons with plasmonic resonators enables control of light-matter interaction at the subwavelength scale. Here we develop such strong coupling in plasmonic nanogap resonators, which allows modification of exciton strength by altering electromagnetic environments in nearby semiconductor monolayers. Using this system, we not only demonstrate a large vacuum Rabi splitting up to 163 meV and splitting features in photoluminescence spectra but also reveal that the effective exciton number contributing to the coupling can be reduced down to the single-digit level (N<10), which is 2 orders lower than that of previous systems, close to single-exciton based strong coupling. In addition, we prove that the strong coupling process is not affected by the large exciton coherence size that was previously believed to be detrimental to the formation of plasmon-exciton interaction. We provide a deeper understanding of strong coupling in two-dimensional semiconductors, paving the way for room-temperature quantum optics applications.
二维半导体激子与等离子体谐振器的强耦合能够在亚波长尺度上控制光与物质的相互作用。在此，我们在等离子体纳米间隙谐振器中实现了这种强耦合，它能通过改变附近半导体单层中的电磁环境来改变激子强度。利用该系统，我们不仅展示了高达163毫电子伏特的大真空拉比分裂以及光致发光光谱中的分裂特征，还揭示了对耦合有贡献的有效激子数可降低至个位数水平（N<10），这比之前的系统低2个数量级，接近基于单激子的强耦合。此外，我们证明了强耦合过程不受先前认为对等离子体激子相互作用形成不利的大激子相干尺寸的影响。我们对二维半导体中的强耦合有了更深入的理解，为室温量子光学应用铺平了道路。
