School of Information and Control Engineering, China University of Mining and Technology

与传统甲烷传感器相比，超表面甲烷传感器具有高度灵敏、性能稳定、小型化、集成化、多功能可定制等优点，更满足在煤矿等复杂环境下的应用需求。设计了基于Fano共振的全介质型超表面甲烷传感器。超表面结构由周期性的硅纳米结构和SiO2衬底组成，包含4个方形硅环纳米结构及中心的硅纳米方块。通过改变几何参数观察其对全介质超表面结构Fano共振的影响，结果表明，综合考虑结构的品质因数和调制深度，应选取方形硅环中心距离为1 000 nm，方形硅环的内边长为100 nm，硅纳米块的边长为200 nm，此时品质因数为227.60，调制深度为99.98%，接近100%。通过在超表面结构内涂覆甲烷气敏薄膜实现传感检测功能，结合极窄线宽的Fano谐振特性和显著的局域场增强效应，实现对甲烷气体的高精度检测。仿真结果表明：全介质超表面传感器对甲烷体积分数的灵敏度为−0.953 nm/%，且甲烷体积分数变化与共振峰偏移量呈线性关系，监测性能较好；全介质超表面传感器的折射率灵敏度高达883.95 nm/RIU，且共振峰偏移量与环境折射率增量呈线性关系，可用于检测环境折射率的变化。

Compared with traditional methane sensors, metasurface methane sensors have advantages such as high sensitivity, stable performance, miniaturization, integration, and multi functional customizability. It better meets the application needs in complex environments such as coal mines. This paper proposes an all dielectric type metasurface methane sensor based on Fano resonance. The metasurface structure consists of periodic silicon nanostructures and SiO2 substrates, consisting of four square silicon ring nanostructures and a central silicon nanoblock. By changing the geometric parameters, the effect on the Fano resonance of the all dielectric metasurface structure is observed. The results show the following points. Considering the quality factor and modulation depth of the structure, the center distance of the square silicon ring should be 1000 nm, the inner edge length of the square silicon ring should be 100 nm, and the edge length of the silicon nanoblock should be 200 nm. At this time, the quality factor is 227.60, and the modulation depth is 99.98%, which is close to 100%. By coating methane gas sensing thin films within the metasurface structure to achieve sensing and detection functions, combined with the extremely narrow linewidth Fano resonance features and significant local field enhancement effect, high-precision detection of methane gas is achieved. The simulation results show that the sensitivity of the all dielectric metasurface sensor to methane volume fraction is −0.953 nm/%. The change in methane volume fraction is linearly related to the shift of the resonance peak, indicating good monitoring performance. The refractive index sensitivity of the all dielectric metasurface sensor is as high as 883.95 nm/RIU. The resonance peak offset is linearly related to the environmental refractive index increment, which can be used to detect changes in environmental refractive index.

国家重点研发计划项目（2021YFC2902702，2021YFC2902703，2021YFC2902704）；国家自然科学基金项目（51874301）。

刘海，周彤，陈聪，等. 基于Fano共振的全介质型超表面甲烷传感器设计[J]. 工矿自动化，2023，49（9）：106-114.

LIU Hai, ZHOU Tong, CHEN Cong, et al. Design of all dielectric metasurface methane sensor based on Fano resonance[J]. Journal of Mine Automation，2023，49（9）：106-114.