MIM波导内嵌金属板结构Fano共振传感特性

Sensing Characteristics of Fano Resonance in MIM Waveguide with Embedded Metal Plate Structure

摘要:

基于法诺(Fano)共振传感特性,提出了一种金属-介质-金属(MIM)波导耦合矩形腔结构,目的是为了实现高灵敏度、高可靠性的折射率传感检测。通过耦合模理论和有限元数值模拟仿真,分析了矩形腔中有无内嵌金属板两种结构的Fano透射光谱特征,并且进一步优化了矩形腔内嵌金属板结构参数,最后阐明了结构参数对其传感特性的内在影响。结果表明,当入射光以TM模式入射到矩形谐振腔时,会形成两个Fano模式共振峰:第一种模式的品质因数(FOM)达9.4×10⁴,灵敏度为700nm/RIU；第二种模式的FOM达8.4×10³,灵敏度为1200nm/RIU。研究结果表明此结构设计实现了双Fano峰检测,同时各个模式品质因数都很高,这为高性能微纳光学折射率传感器的设计提供了一定的理论参考依据。

Abstract:

In order to achieve highly sensitive and reliable sensing detection of refractive index, a metal-insulator-metal (MIM) waveguide coupled rectangular cavity structure is proposed based on sensing performance of Fano resonance in this paper. With the help of theoretical analysis of the coupling mode and the numerical simulation by the finite element method, the Fano transmission spectral characteristics of the rectangular cavity with and without embedded metal plate are analyzed. And the parameters of the designed rectangular cavity embedded metal plate structure are optimized further. Finally, the influence of structural parameters on its sensing characteristics is discussed. The results show that two Fano mode resonant peaks are formed after light is incident into the rectangular resonant cavity with TM mode. In the first mode, the FOM is 9.4×10⁴ and the sensitivity is 700nm/RIU; in the second mode, the FOM is 8.4×10³ and the sensitivity is 1200nm/RIU. The results indicate that bimodal detection can be achieved in this structure and a high quality factor can be achieved also in each model, which provides a theoretical basis for the design of high performance micro/nano optical refractive index sensor.