MIM波导矩形腔内嵌金属板结构Fano共振的传感特性

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

摘要:

为实现对折射率的高灵敏、高可靠性传感探测，根据法诺（Fano）共振传感的特点，本文提出了一种金属—介质—金属（MIM）波导耦合的矩形腔结构，实现对Fano共振的高性能探测。在耦合模理论分析及有限元法数值仿真的基础上，先对比分析矩形腔与其嵌入金属板两种不同结构的Fano透射光谱特征，再对设计的矩形腔嵌入金属板结构参数进行优化并分析其传感性能。入射光在波导中以TM模式入射到矩形谐振腔后形成了两种Fano模式的共振峰。第一种模式的FOM达 9.4104，灵敏度为700nm/RIU；第二种模式的FOM达 8.4103，其灵敏度为1200nm/RIU。这表明该结构设计在实现双Fano峰探测的同时，且各个模式均具有较高的品质因数，这为设计出高性能的微纳光学传感器提供理论依据。

Abstract:

In order to achieve highly sensitive and reliable sensing detection of refractive index, according to the characteristics of Fano resonance sensing, a metal-medium-metal (MIM) waveguide coupled rectangular cavity structure is proposed in this paper to achieve high performance detection of Fano resonance. Based on the theoretical analysis of the coupling mode and the numerical simulation by the finite element method, the Fano transmission spectral characteristics of the rectangular cavity and its embedded metal plate are first compared and analyzed, and then the parameters of the designed rectangular cavity embedded metal plate structure are optimized and its sensing performance is analyzed. Two Fano mode resonant peaks are formed after incident light is incident in the waveguide in TM mode into the rectangular resonant cavity. The first mode has FOM of 9.4104 and a sensitivity of 700nm/RIU, while the second mode has FOM of 8.4103 and a sensitivity of 1200 nm/RIU. This indicates that the structure is designed to achieve dual Fano peak detection with high quality factors for each mode, which provides a theoretical basis for the design of a high-performance micro and nano optical sensor.