A refractive index sensor based on Fano resonances in metal-insulator-metal （MIM） waveguides coupled with rectangular and dual side rings resonators is proposed. The sensing properties are numerically simulated by t...A refractive index sensor based on Fano resonances in metal-insulator-metal （MIM） waveguides coupled with rectangular and dual side rings resonators is proposed. The sensing properties are numerically simulated by the finite element method （FEM）. For the interaction of the narrow-band spectral response and the broadband spectral response caused by the side-coupled resonators and the rectangular resonator, respectively, the transmission spectra exhibit a sharp and asymmetric profile. Results are analyzed using the coupled-mode theory based on the transmission line theory. The coupled mode theory is employed to explain the Fano resonance effect. The results show that with an increase in the refractive index of the fill dielectric material in the slot of the system, the Fano resonance peak exhibits a remarkable red shift. Through the optimization of structural parameters, we achieve a theoretical value of the refractive index sensitivity （S） as high as 1160 nm/RIU, and the corresponding sensing resolution is 8.62 × 10 -5 RIU. In addition, the coupled MIM waveguide structure can be easily extended to other similar compact structures to realize the sensing task and integrated with other photonic devices at the chip scale. This work paves the way toward the sensitive nanometer scale refractive index sensor for design and application.展开更多
We present three important extensions of the plasmon hybridization(PH)method:a generalization of the method to include realistic non-Drude dielectric permittivities for metals,the development of an algorithm for the c...We present three important extensions of the plasmon hybridization(PH)method:a generalization of the method to include realistic non-Drude dielectric permittivities for metals,the development of an algorithm for the calculation of plasmon-induced electric field enhancements,and the extension of the PH method to the modeling of plasmonic Fano resonances.We illustrate these developments with an application to a silver nanosphere dimer and a symmetric silver nanosphere heptamer.展开更多
Multiple Fano resonances of plasmonic nanostructures have attracted much attention due to their potential applications in multicomponent biosensing. In this paper, we propose a series of hybridized nanostructures cons...Multiple Fano resonances of plasmonic nanostructures have attracted much attention due to their potential applications in multicomponent biosensing. In this paper, we propose a series of hybridized nanostructures consisting of a single nanoring and multiple nanorods to generate multiple Fano resonances. One to three Fano resonances are achieved through tuning the number of nanorods. The interaction coupling process between different components of the nanostructures is recognized as the mechanism of multiple Fano resonances. We also theoretically investigate the applications of the produced multiple Fano resonances in refractive index sensing. The specific properties of multiple Fano resonances will make our proposed nanostructures beneficial to high-sensitivity biosensors.展开更多
为克服等离子体波导系统存在结构复杂、可利用波段范围小以及可调性差的缺点,提出了一种简单的双半环型腔金属-绝缘体-金属等离子激元波导结构(double semi-ring,DSR)。利用有限元法(finite element method,FEM)对其进行了模拟计算,并...为克服等离子体波导系统存在结构复杂、可利用波段范围小以及可调性差的缺点,提出了一种简单的双半环型腔金属-绝缘体-金属等离子激元波导结构(double semi-ring,DSR)。利用有限元法(finite element method,FEM)对其进行了模拟计算,并通过调整结构的几何参数和介质折射率,研究了该结构的透射特性和传感特性。结果发现:DSR结构能够产生2个典型的法诺共振,并且窄的离散态对法诺共振的形成起主导作用。改变共振腔的宽度和耦合距离可以实现对法诺共振的独立调控,该结构的最大折射率灵敏度和品质因数分别为1260 nm/RIU和17473 RIU^(-1)。通过在DSR结构的基础上添加共振腔可以实现四重法诺共振和法诺共振的半独立调控。提出的等离子激元波导结构简单且能产生透射率大、可调性好和灵敏感度高的多重法诺共振,可用于滤波器、光开关和传感器等领域。展开更多
基金The authors thank Xiangxian WANG from the School of Science, Lanzhou University of Technology, Lanzhou, China for their discussions to this research. This work is supported by the National Natural Science Foundation of China （Grant Nos. 61367005 and 74011119） and the Natural Science Foundation of Gansu Province （Grant No. 17JR5RA078）.
文摘A refractive index sensor based on Fano resonances in metal-insulator-metal （MIM） waveguides coupled with rectangular and dual side rings resonators is proposed. The sensing properties are numerically simulated by the finite element method （FEM）. For the interaction of the narrow-band spectral response and the broadband spectral response caused by the side-coupled resonators and the rectangular resonator, respectively, the transmission spectra exhibit a sharp and asymmetric profile. Results are analyzed using the coupled-mode theory based on the transmission line theory. The coupled mode theory is employed to explain the Fano resonance effect. The results show that with an increase in the refractive index of the fill dielectric material in the slot of the system, the Fano resonance peak exhibits a remarkable red shift. Through the optimization of structural parameters, we achieve a theoretical value of the refractive index sensitivity （S） as high as 1160 nm/RIU, and the corresponding sensing resolution is 8.62 × 10 -5 RIU. In addition, the coupled MIM waveguide structure can be easily extended to other similar compact structures to realize the sensing task and integrated with other photonic devices at the chip scale. This work paves the way toward the sensitive nanometer scale refractive index sensor for design and application.
基金supported by the Robert A.Welch Foundation(C-1222)the National Science Foundation(CNS-0421109)
文摘We present three important extensions of the plasmon hybridization(PH)method:a generalization of the method to include realistic non-Drude dielectric permittivities for metals,the development of an algorithm for the calculation of plasmon-induced electric field enhancements,and the extension of the PH method to the modeling of plasmonic Fano resonances.We illustrate these developments with an application to a silver nanosphere dimer and a symmetric silver nanosphere heptamer.
基金The National Natural Science Foundation of China(Nos.61502538,61501525)the Nature Science Foundation for Young Scientists of Hunan Province,China(No.2015JJ3157)the Graduate Scientific Research Foundation of Central South University(No.2017zzts699)
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674275,11601469,and 61505174)the Natural Science Foundation of Hebei Province,China(Grant Nos.F2016203282,C2014203212,and E2016203185)the Science and Technology Research Project of Hebei Higher Education Institutions,China(Grant No.QN2018071)
文摘Multiple Fano resonances of plasmonic nanostructures have attracted much attention due to their potential applications in multicomponent biosensing. In this paper, we propose a series of hybridized nanostructures consisting of a single nanoring and multiple nanorods to generate multiple Fano resonances. One to three Fano resonances are achieved through tuning the number of nanorods. The interaction coupling process between different components of the nanostructures is recognized as the mechanism of multiple Fano resonances. We also theoretically investigate the applications of the produced multiple Fano resonances in refractive index sensing. The specific properties of multiple Fano resonances will make our proposed nanostructures beneficial to high-sensitivity biosensors.
