单挡板金属-电介质-金属波导耦合圆盘腔级联多Fano共振差动传感

Multi-Fano Resonance Differential Sensing by Single-Baffle Metal-Dielectric-Metal Waveguide Coupled Disk Cavity Cascade

基于表面等离子亚波长结构的传输特性与光子局域特性,提出了一种单挡板金属-电介质-金属(MDM)波导耦合圆盘级联结构。由圆盘级联形成的孤立态与金属挡板形成的较宽连续态干涉相长相消,形成了两种不同模式的Fano共振。结合耦合模理论,分析了该结构形成Fano共振的传输特性,采用有限元分析法对结构进行了模拟仿真,定量分析了结构参数对折射率传感特性影响。根据折射率变化的物理机制,分析了温度和湿度在实际测量过程中对测量结果的影响,并采用差动传感的方法有效解决了传感过程中的交叉敏感问题。

A single-baffle metal-dielectric-metal(MDM) waveguide coupled disk cavity cascade structure is proposed based on the transmission characteristics and photon local characteristics of the surface-plasmon-based sub-wavelength structures. The discrete state provided by the side-coupled disk cavity cascade and is used to provide a continuous state produced by the baffle plate placed in metal-dielectric-metal waveguide interferes constructively or destructively, and thus two different modes of Fano resonance are formed. The transmission characteristics of the formed Fano resonance are analyzed according to the coupled mode theory. The structure is simulated by the finite element analysis method and the effects of the structural parameters on the refractive index sensing characteristics are quantitatively analyzed. The effects of temperature and humidity on the measurement results in the actual measurement process are analyzed, based on the physical mechanism underlying the refractive index change. Moreover, the problem of cross-sensitivity in the sensing process is effectively solved by the differential sensing method.