Future quantum information devices will most likely rely on the realization of coherent light-matter interactions in strong coupling regime and the maintaining of the coherence with minimized incoherent damping pathways. Here, utilizing film-coupled planar nanoparticle supporting unique plasmon-induced magnetic resonance (PIMR), we theoretically study a strong coupling of a single nanocube to a monolayer of two-dimensional atomic crystal. We demonstrate that the nanocube-based planar configuration with magnetic flux passing through the dielectric layer exhibits much higher in-plane field confinement with respect to traditional plasmon electric modes, leading to an efficient coherent coupling to only a few in-plane excitonic dipoles with a record of normal mode splitting over 280 meV. Importantly, a much reduced incoherent coupling strength down to 3 meV is obtained. We reveal that the underlying mechanism lies in two main facts: (i) the small radiative damping rate of the excitonic system giving very limited contribution to the linewidth broadening of the A-exciton resonance, and (ii) the excitation of magnetic resonance provides a net electric dipole moment orientating mainly normal to the film surface, thus greatly suppressing the exchange of photons between the two subsystems via the continuum reservoir. The numerical simulations and theoretical analysis quantitatively evaluate the dependence of both the coherent and incoherent coupling strength on the thickness of the dielectric layer, revealing the fact that coherent/incoherent coupling strength can be simultaneously enhanced/suppressed with the decrease/increase of the film thickness, which can be appropriately designed to achieve the optimal coherent coupling with minimized incoherent coupling strength. Such hybrid nanostructure with simple geometry and ease of fabrication may not only offer as an attractive platform to explore light-matter interaction in the strong coupling regime but also show potential applications in realizing novel quantum and nanophotonic optical devices.

中文翻译：

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抑制非相干阻尼路径，增强单层WS2与膜耦合纳米立方体开孔之间的相干相互作用

未来的量子信息设备将最有可能依赖于在强耦合机制中实现相干光-物质相互作用以及在最小化非相干阻尼路径的情况下保持相干性。在这里，利用支持独特的等离子体激元感应磁共振（PIMR）的薄膜耦合平面纳米颗粒，我们从理论上研究了单个纳米立方体与二维原子晶体单层的强耦合。我们证明，相对于传统的等离激元电模，具有通过磁介质层的磁通量的基于纳米立方体的平面结构展现出更高的面内电场约束，从而导致仅与几个面内激子偶极的有效相干耦合。正常模式分裂超过280 meV的记录。重要的，可以将非相干耦合强度降低到3 meV。我们揭示了潜在的机理在于两个主要事实：（i）激子系统的辐射衰减率小，对A激子共振的线宽加宽贡献很小，并且（ii）磁共振激发提供了净电偶极矩主要垂直于薄膜表面定向，因此极大地抑制了两个子系统之间通过连续介质储集层进行的光子交换。数值模拟和理论分析定量评估了相干和非相干耦合强度对介电层厚度的依赖性，这揭示了可以通过减小/增加膜厚度同时增强/抑制相干/非相干耦合强度这一事实，可以适当地设计该膜以在最小化非相干耦合强度的情况下实现最佳相干耦合。这种具有简单几何形状和易于制造的杂化纳米结构不仅可以提供一个有吸引力的平台来研究强耦合状态下的光-质相互作用，而且在实现新型量子和纳米光子光学器件方面显示出潜在的应用。