A plasmonic structure, constituted by metal insulator metal waveguides and split annular cavity connected with rectangular resonator (SACRR), is proposed and investigated. Numerical simulation by the finite element method (FEM) has been done to investigate the transmittance properties of the proposed structure and four Fano resonances arise in the results. To analyze and verify the simulation results, multimode interference coupled mode theory is engaged, theoretically. In addition, the structural parameters are analyzed and discussed to design and control the proposed structure, which shows sufficient flexibility. Due to multi-Fano resonances providing multiple monitoring points and the extremely sharp asymmetry of Fano resonance, the structure can service as a high-performance multichannel refractive index nanosensor with a sensitivity of 1000 nm/RIU and maximum figure of merit of 1.358 × 105. The designed structure can surely meet extensive applications for nanoscale devices and integrated optical devices.

中文翻译：

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MIM波导中的多扇共振与与矩形谐振器连接的分离环形腔耦合以及在多通道折射率传感器中的应用

提出并研究了一种由金属绝缘体金属波导和与矩形谐振器（SACRR）相连的分裂环形腔构成的等离子体结构。通过有限元方法（FEM）进行了数值模拟，以研究该结构的透射特性，结果产生了四个Fano共振。为了分析和验证仿真结果，理论上采用了多模干扰耦合模式理论。此外，对结构参数进行了分析和讨论，以设计和控制所提出的结构，这显示了足够的灵活性。由于提供了多个监控点的多费诺共振和费诺共振极为不对称，