MDM波导耦合M型谐振腔的折射率传感性能  

Analysis of Refractive Index Sensing Performance of MDM WaveguideCoupled with an M-shaped Resonant Cavity

作　　者：许蒲城 关建飞 XU Pucheng;GUAN Jianfei(College of Electronic and Optical Engineering&College of Flexible electronics(Future technology),University of Posts and Telecommunications,Nanjing,Jiangsu 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,江苏南京210023

出　　处：《计算物理》2025年第1期57-64,共8页Chinese Journal of Computational Physics

基　　金：国家自然科学基金(61775102,61905117);南京邮电大学科研基金(NY220050,NY214058)资助。

摘　　要：提出一种金属-电介质-金属(MDM)波导侧向耦合M型谐振腔实现高灵敏度折射率传感的等离激元波导结构。采用有限元分析法定量分析谐振腔结构参数及填充介质折射率对MDM波导透射谱线的定量影响。仿真结果显示:M型腔中的一到四阶类法布里-珀罗(FP)谐振模式与MDM主波导中金属挡板产生的反射导波模式进行耦合干涉形成四重Fano共振透射峰。该透射峰不仅具有非对称谱线形状及陡峭边沿分布,而且峰值波长随腔长及填充媒质折射率的改变呈现近似线性变化的规律。选取长宽为400 nm×400 nm的M型谐振腔可以产生最高灵敏度为4900 nm/RIU的一阶Fano共振透射峰。计算结果显示:传感灵敏度与谐振腔长成正比及与谐振阶次成反比的变化规律,为高灵敏度传感器的设计提供参考。A high sensitivity refractive index sensor have been proposed in this paper,which is composed by an M-shaped resonant cavity coupled with a baffle contained Metal-Dielectric-Metal(MDM)waveguide.The influence of structural parameter of M-shaped cavity and filled medium characteristics inside it on the transmission spectrum of MDM waveguide have been analyzed numerically through the finite element method.Simulation results show that four asymmetric transmission peaks with Fano line-shape are generated by the coupling interference between the four quasi Fabry-Perot(FP)resonant modes of the first to fourth orders inside M-shaped cavity and the reflected wave in MDM waveguide,moreover the four peak wavelengths redshift almost linearly with increasing cavity length or the refractive index of the filled medium,which can be used to design the refractive index sensor.The calculated sensitivities associated with the quadruple Fano transmission peaks are found to be proportional to the cavity length and the reciprocal of resonant order.As a consequence,a sensitive up to 4900 nm/RIU has been realized by an M-shaped resonator in dimensions of 400 nm×400 nm.The results in the article provide an effective guidance for the design of high sensitivity sensors.

关 键 词：表面等离激元 MDM波导 M型腔 Fano共振 有限元法 

分 类 号：O436[机械工程—光学工程]