金属-介质-金属多层结构可调谐Fabry-Perot共振及高灵敏折射率传感  

Metal-dielectric-metal multilayer structure with tunable Fabry-Perot resonance for highly sensitive refractive index sensing

作　　者：张翔宇[1,2,3] 刘会刚 康明[4] 刘波 刘海涛 Zhang Xiang-Yu;Liu Hui-Gang;Kang Ming;Liu Bo;Liu Hai-Tao(Engineering Research Center of Thin Film Optoelectronics Technology,Ministry of Education,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology,Tianjin 300350,China;Department of Microelectronic Engineering,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;College of Physics and Materials Science,Tianjin Normal University,Tianjin 300387,China;Institute of Modern Optics,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology,Tianjin 300350,China)

机构地区：[1]南开大学,薄膜光电子技术教育部工程研究中心,天津300350 [2]天津市光电传感器与传感网络技术重点实验室,天津300350 [3]南开大学电子信息与光学工程学院,天津300350 [4]天津师范大学物理与材料科学学院,天津300387 [5]南开大学电子信息与光学工程学院,现代光学研究所,天津300350 [6]天津市微尺度光学信息技术科学重点实验室,天津300350

出　　处：《物理学报》2021年第14期105-114,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62075104,61775105,11674244)资助的课题.

摘　　要：顶层透光、底层不透光的金属-介质-金属多层结构可以产生窄带完美吸收共振,用于测量介质层待测液体的折射率变化.本文通过构建Fabry-Perot共振解析模型,准确复现了该结构的响应光谱,给出了其共振波长、品质因子、半高全宽和灵敏度的解析表达式,并分析了介质层厚度对光谱的谐振波长和线宽的调谐机制,明确了其物理机理.基于8阶Fabry-Perot共振的金属-介质-金属多层结构,用于折射率传感时的品质因子及优值分别达到2162.8和1648.1 RIU-1.针对极小的折射率扰动,通过在奇异点状态叠加Fabry-Perot共振的调谐机制,提出了通过测量奇异点波长处反射系数的增加量或散射矩阵本征值的分裂量,实现对待测液体折射率的可调谐式传感的方案.Fabry-Perot模型解析结果显示,当待测液体的折射率变化为10-4 RIU时,基于8阶Fabry-Perot共振的金属-介质-金属多层结构的前向反射系数增加量和本征值分裂量分别达到0.319和1.1279.The metal-dielectric-metal multilayer structure sensor with a transparent top layer and an opaque bottom layer is proposed,which can provide a perfect narrow-band absorption resonance and is suitable for sensing refractive index change of the liquid to be measured in dielectric layer.The Fabry-Perot resonance analytical model that can accurately reproduce response spectrum and theoretically analyze the mechanism of the dielectric layer thickness to tune resonance wavelength and linewidth of response spectrum is constructed.Theoretical analysis shows that the resonance wavelength is directly proportional to the thickness of dielectric layer,and the full width at half maximum is inversely proportional to the thickness of dielectric layer.The analytical expressions for its resonance wavelength,quality factor,full width at half maximum and sensitivity are also given.When used for the refractive index sensing,the quality factor and figure of merit of the proposed multilayer structure based on the 8th order Fabry-Perot resonance are 2162.8 and 1648.1 RIU–1,respectively.However,due to the influence of the minimum resolution of the spectrometer,the conventional method of measuring resonance wavelength shift to achieve refractive index sensing has a high measurement limit.For the sensing of weaker refractive index perturbation,with the help of superposition of exceptional point degenerate state and tuning mechanism of Fabry-Perot resonance,in this paper proposed is a method of tunably sensing the liquid refractive index by measuring the increase of reflection coefficient or splitting of eigenvalue at a specific wavelength.Here,we take for example the metal-dielectric-metal multilayer structure sensor based on the 8th order Fabry-Perot resonance.According to the calculation results of Fabry-Perot model,when the change in refractive index of liquid to be measured is 10–4 RIU,the increase of forward reflection coefficient and the splitting of two eigenvalues of the scattering matrix are 0.319 and 1.1279,respectively.

关 键 词：金属-介质-金属谐振器 FABRY-PEROT 共振模型 可调谐式传感 奇异点 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]