Mahmoud Mohamed, AlMotasem A T, Abd-Elrahman M I, Shaalan Nagih M, Rashad Mohamed, Fares Hesham
Department of Physics, Faculty of Science, Assiut University, Assiut 71516, Egypt.
Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 160 00, Czechia.
J Chem Phys. 2025 Sep 7;163(9). doi: 10.1063/5.0277425.
In close proximity to quantum emitters (QEs), plasmonic nanoparticles (NPs) facilitate energy exchange with the QEs, which is known as plasmon-exciton coupling. The strong coupling regime, associated with Rabi splitting, is crucial for advanced nanophotonic devices, including solar cells, single-photon nonlinear optics, and nanolasers. Recently, high refractive index semiconductor NPs (typically Si NPs) have emerged for designing strongly coupled systems. However, their large mode volumes of magnetic Mie resonances have limited their success in achieving strong coupling. This study investigates the plasmon-exciton coupling between an Ag-Si core-shell and a monolayer QE of WS2 (Ag-Si-WS2 system) in air and water environments. Here, we compare the coupling dynamics of the hybrid Ag-Si-WS2 system to that of the Si-WS2 system as a benchmarking system. Employing Mie's theory of core-shell scattering, in conjunction with Maxwell-Garnett effective medium theory, we analyze the optical responses of both configurations. Then, we calculate the Rabi splitting frequency for each system to identify the coupling regime. Our results suggest that the Ag-Si-WS2 system can achieve a deep-strong coupling regime when the Ag core radius is less than 30 nm, with enhanced coupling strength in water compared to air. Conversely, the Si-WS2 system does not achieve strong coupling in either medium. The hybrid modes in Ag-Si-WS2 demonstrate remarkable symmetrical spectral characteristics compared to the asymmetric spectral line shape observed in the Si-WS2 system. The findings suggest avenues for utilizing the plasmon-exciton strong coupling in the Ag-Si-WS2 system to enhance optoelectronic and quantum electronic devices.
在量子发射器（QE）附近，等离子体纳米颗粒（NP）促进与QE的能量交换，这被称为等离子体激元 - 激子耦合。与拉比分裂相关的强耦合 regime 对于包括太阳能电池、单光子非线性光学和纳米激光器在内的先进纳米光子器件至关重要。最近，高折射率半导体NP（通常是Si NP）已出现用于设计强耦合系统。然而，它们磁米氏共振的大模式体积限制了它们在实现强耦合方面的成功。本研究调查了空气和水环境中Ag - Si核壳与单层WS2的QE（Ag - Si - WS2系统）之间的等离子体激元 - 激子耦合。在这里，我们将混合Ag - Si - WS2系统的耦合动力学与作为基准系统的Si - WS2系统的耦合动力学进行比较。利用米氏核壳散射理论，结合麦克斯韦 - 加尼特有效介质理论，我们分析了两种配置的光学响应。然后，我们计算每个系统的拉比分裂频率以确定耦合 regime。我们的结果表明，当Ag核半径小于30 nm时，Ag - Si - WS2系统可以实现深度强耦合 regime，与空气相比，在水中耦合强度增强。相反，Si - WS2系统在两种介质中均未实现强耦合。与Si - WS2系统中观察到的不对称光谱线形状相比，Ag - Si - WS2中的混合模式表现出显著的对称光谱特征。这些发现为利用Ag - Si - WS2系统中的等离子体激元 - 激子强耦合来增强光电器件和量子电子器件提供了途径。
