基于多孔金膜的太赫兹导模共振生化传感特性仿真  

Performance simulation of terahertz waveguide resonance biochemical sensor based on nanoporous gold films

作　　者：杨泽浩 刘紫威 杨博 张成龙 蔡宸 祁志美 Yang Ze-Hao;Liu Zi-Wei;Yang Bo;Zhang Cheng-Long;Cai Chen;Qi Zhi-Mei(State Key Laboratory of Transducer Technology,Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100190,China;School of Electronic,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院空天信息创新研究院,传感技术国家重点实验室,北京100190 [2]中国科学院大学电子电气与通信工程学院,北京100049

出　　处：《物理学报》2022年第21期403-413,共11页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2021YFB3200100);国家自然科学基金(批准号:62121003,61931018,61871365)资助的课题。

摘　　要：仿真设计了一种高灵敏度太赫兹(THz)导模共振生化传感结构.该结构由硅棱镜、介质薄膜和多孔金膜组成,多孔金膜同时作为THz导波层和生化分子富集层,能够增强THz导模与生化分子间的相互作用,从而提高探测灵敏度.当采用棱镜全反射方法激励THz横电(TE)或横磁(TM)导模后,多孔金膜的吸收使得THz反射频谱出现尖锐的共振吸收峰,由此可确定THz导模的共振频率及其对液体折射率和生化分子吸附量的灵敏度.调节介质层的厚度和折射率可进一步提高上述THz传感结构的灵敏度和品质因数.在45°入射角下的仿真结果指出,TE和TM导模的共振频率随着液体折射率或生化分子吸附量的增大而线性变化,TM导模的折射率灵敏度可高达13.42 THz/RIU,品质因数达到167.70/RIU,TE导模对液体折射率的灵敏度小于TM导模,但对分子吸附量的灵敏度大于TM导模,究其原因是TE导模透出多孔金膜的消逝场比TM导模弱.A highly sensitive terahertz(THz)waveguide resonance biochemical sensor is designed and simulated.The sensor consists of a silicon prism,a dielectric layer and a nanoporous gold film.The nanoporous gold film acts as both a THz waveguiding layer and a biochemical molecular enrichment layer,which can enhance the interaction between the THz waveguide mode and the adsorbed biochemical molecules,consequently improving the sensor’s sensitivity.When the THz transverse electric(TE)or transverse magnetic(TM)modes are excited by the prism-coupling method,the THz absorption of the nanoporous gold film results in the sharp resonance dips in the THz reflection spectrum.The resonance frequencies of the THz waveguide modes and the sensitivity to either liquid refractive index(RI)or adsorbed molecules can be determined with the measured reflection spectra,and the sensor’s sensitivity and its figure of merit(FOM)can be improved by adjusting the thickness and RI of the dielectric layer.The simulation results at 45°incidence angle indicate that the resonance frequencies of the TE and TM modes of the sensor linearly change with increasing either liquid RI or the amount of adsorbed molecules,and the RI sensitivity and the FOM with the TM mode are 13.42 THz/RIU and 167.70/RIU,respectively.Compared with the TM mode,the TE mode has a lower sensitivity to lqiuid RI but a high sensitivity to adsorbed molecules.The reason for these differences is that with the TE mode the evanescent field penentrating out of the nanopous gold film is weaker than that with the TM mode.

关 键 词：太赫兹 纳米多孔金膜 生化传感 高灵敏度 

分 类 号：O441.4[理学—电磁学]