Shao Zhiquan, Yan Shubin, Wen Feng, Wu Xiushan, Hua Ertian
Appl Opt. 2021 Aug 1;60(22):6623-6631. doi: 10.1364/AO.426629.
A novel nanosensor based on a metal-insulator-metal waveguide coupled to a double ring resonator is proposed. The spectral characteristics are studied by finite element method, and a Fano resonance (FR) formed by the interference of the narrowband mode and the broadband mode is discovered. After analyzing the effects of structural parameters on the transmission characteristics, the structure is further optimized by adding a rectangular cavity inside the ring cavity. The maximum sensitivity reaches 1885 nm/RIU with the figure of merit (FOM) of 77. Additionally, a tunable multiple FR system is realized through the derivative structure, which leads to the splitting of the resonance mode and produces two new narrowband modes. Their formation mechanism and performance are studied through a normalized magnetic field distribution and transmission spectrum. The designed structure with excellent performance can discover significant applications in the future nanosensing domain.
提出了一种基于金属-绝缘体-金属波导耦合双环谐振器的新型纳米传感器。采用有限元法研究了其光谱特性，发现了由窄带模式和宽带模式干涉形成的法诺共振（FR）。在分析结构参数对传输特性的影响后，通过在环形腔内添加矩形腔对结构进行了进一步优化。最大灵敏度达到1885 nm/RIU，品质因数（FOM）为77。此外，通过衍生结构实现了可调谐多FR系统，导致共振模式分裂并产生两个新的窄带模式。通过归一化磁场分布和传输光谱研究了它们的形成机制和性能。所设计的具有优异性能的结构在未来的纳米传感领域具有重要应用。
