Wu Fan, Zhang Wei
Opt Express. 2025 Mar 10;33(5):10150-10164. doi: 10.1364/OE.543361.
Strong light-matter interaction in plexcitonic systems plays a crucial role in both fundamental quantum optics study and practical applications, including quantum information processing and nanophotonic devices. However, despite strong light confinement associated with plasmons, large damping of plasmonic cavities remains a major obstacle to achieving strong coupling, particularly with single exciton. Here, we introduce a novel platform that achieves strong coupling via leveraging dark plasmon mode to reduce the loss of the system rather than only enhancing the coupling strength to overcome the system's large damping. Optical properties of the bright/dark modes supported by different silver nanorod dimers are studied, revealing the connection between symmetric configurations and the properties of these resonant modes. The dark mode of side-by-side silver nanorod dimer exhibits an ultralow loss of approximately 22 meV, dramatically decreasing the harsh requirement in coupling strength and enabling strong coupling with a single quantum dot. The time-domain and frequency-domain characteristics of the bright/dark mode-exciton coupling system are compared in detail. Furthermore, a new scheme based on symmetry breaking is proposed to realize the coupling state control across three coupling regimes with different time-domain and frequency-domain characteristics.
激子极化子系统中的强光-物质相互作用在基础量子光学研究和实际应用中都起着至关重要的作用，包括量子信息处理和纳米光子器件。然而，尽管表面等离子体激元具有很强的光限制作用，但表面等离子体激元腔的大阻尼仍然是实现强耦合的主要障碍，特别是与单激子的耦合。在此，我们引入了一种新型平台，该平台通过利用暗表面等离子体激元模式来降低系统损耗，而不是仅增强耦合强度来克服系统的大阻尼，从而实现强耦合。研究了由不同银纳米棒二聚体支持的亮/暗模式的光学性质，揭示了对称构型与这些共振模式性质之间的联系。并排银纳米棒二聚体的暗模式表现出约22毫电子伏特的超低损耗，大大降低了对耦合强度的苛刻要求，并能够与单个量子点实现强耦合。详细比较了亮/暗模式-激子耦合系统的时域和频域特性。此外，还提出了一种基于对称性破缺的新方案，以实现跨越具有不同时域和频域特性的三种耦合区域的耦合状态控制。
