改进型蝴蝶结超表面及在痕量铅离子检测中的应用  

Optimized bow-tie metasurface and its application in trace detection of lead ion

作　　者：张俊卿 吴毅萍 陈晟皓 古诗怡 孙丽[4] 周铭[4] 陈麟[1,2,5] Zhang Junqing;Wu Yiping;Chen Shenghao;Gu Shiyi;Sun Li;Zhou Ming;Chen Lin(College of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Key Laboratory of Modern Optical System,Shanghai 200093,China;The Sino-British Collede,Shanghai 200031,China;Shanghai Academy of Environmental Sciences,Shanghai 200233,China;Institute of Intelligent Science and Technology,Tongji University,Shanghai 200092,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093 [2]上海市现代光学系统重点实验室,上海200093 [3]上海理工大学中英国际学院,上海200031 [4]上海市环境科学研究院,上海200233 [5]同济大学人工智能研究院,上海200092

出　　处：《光电工程》2021年第8期56-65,共10页Opto-Electronic Engineering

基　　金：国家自然科学基金资助项目(61671302);上海市曙光计划资助项目(18SG44);上海市环境科学研究院创新基金资助项目(2020190189)。

摘　　要：超表面具有强烈的局域等离子体共振特性,其共振频率对周围介质环境十分敏感,可应用于无标记环境检测领域。本文设计了一种优化了品质因数和有效模体积之比(Q/Veff)的蝴蝶结型太赫兹超表面结构。该结构单元由中间镜像对称的金属蝴蝶结及两侧的连续金属边带组成。针对Q/Veff这一重要指标,分别从连续金属边带的宽度和蝴蝶结间隙长度这两个参数对结构进行了仿真优化。当连续金属边带宽度为25μm,间隙长度为2μm时,在0.7 THz处有效模体积为3.6μm_(3),相应的Q/Veff为2.2μm^(-3)。在实验中,将不同浓度的铅离子溶液滴于超表面传感器表面,利用太赫兹时域光谱系统测量透射谱。实验结果表明,在0.1 ng/mL~20 ng/mL范围内铅离子溶液浓度与超表面共振频率的漂移值具有线性关系,铅离子溶液的检测最低限为0.1 ng/mL。该太赫兹超表面传感器具有体积小、样品制备简单、检测速度快和实时现场测量等优点,将在环境保护和食品安全领域有广泛应用。The strong localized plasmon resonance of metasurfaces makes the resonance frequency extremely sensitive to the dielectric environment,which can be applied to label-free environment detection.In this paper,a bow-tie terahertz metasurface with an optimized ratio of the quality factor to effective mode volume(Q/Veff)is de-signed.The unit cell of the proposed structure is composed of a mirror-symmetrical metallic bow tie in the middle and continuous metallic strips on both sides.The width of each metal strip and the length of the bow-tie gap are opti-mized for the parameter Q/Veff.When the metal strip width is 25μm and the gap length is 2μm,the effective mode volume is 3.6μm^(3) and Q/Veff is 2.2μm^(-3) at 0.7 THz.In the experiment,different concentration of the lead ion solution was dropped on the proposed metasurface.The transmission spectrum was measured by a terahertz time-domain spectroscopy system.The results showed that there is a linear relationship between resonance frequency shift and lead ion solution concentration from 0.1 ng/mL to 20 ng/mL.The detection limit is 0.1 ng/mL.The terahertz meta-surface sensor has the advantages of the miniaturized size,easy sample preparation,fast measurement capability and real-time detection,which will be widely used in environmental protection and food safety.

关 键 词：太赫兹 超表面 铅离子 有效模体积 高灵敏度 

分 类 号：TH74[机械工程—光学工程] TB33[机械工程—仪器科学与技术]