Study On The Sensing Characteristics Of Coupled Resonator MIM Waveguide Based On Fano Resonance

Optical sensor devices have many advantages,such as anti-electromagnetic interference,fast response speed,low power consumption and low crosstalk.It has been widely concerned by researchers.However,due to the existence of diffraction limit,it is difficult to further integrate optical sensors.The surface plasma can break through the diffraction limit and bring hope to the integration and miniaturization of optoelectronic devices.This paper uses the ability of surface plasma to break through the diffraction limit,excites the Surface Plasmon Polaritons in the MIM waveguide,combines the Fano resonance with sharp resonance peaks,and designs a new refractive index sensor structure.The electromagnetic characteristics of electromagnetic waves in different resonant microcavities are explored,and the sensing characteristics from single peak Fano resonance to multiple Fano resonance are analyzed.The feasibility of multi-parameter sensing and differential sensing using multiple Fano resonance is studied.Designed sensor structure's Sensitivity up to 1050 nm/RIU,Figure Of Merit up to 41147.The specific research work is as follows.On the basis of fully investigating the current research situation at home and abroad,starting from the basic theory of surface plasma,we deeply explored the physical characteristics and excitation mode of surface plasma,studyed the spectral characteristics,formation conditions and internal mechanism of Fano resonance,and analyzed the dispersion relationship of metal surface and the transmission characteristics of MIM waveguides.The structure of ice cream-shaped resonator MIM waveguide sensor with metal baffle is proposed.The Fano resonance with sharp asymmetric wave peak is successfully constructed by using the coupling of continuous state and discrete state under near field action provided by straight waveguide with baffle.Based on the coupling mode theory,the mechanism and electromagnetic characteristics of Fano resonance are discussed.A study on the sensing performance of Fano resonance as a sensing,and the influence of the change of structural parameters on the resonance spectrum is explored.The symmetrical defect cavity is added to the structure of ice cream-shaped resonator.A cloud-shaped resonator MIM waveguide structure embedded with silver nanodisk is proposed.Double Fano resonance is obtained in its transmission spectrum.The sensing characteristics of double Fano resonance in multi-parameter measurement are studied.By analyzing the quality factor,the structural parameters are optimized and the sensing performance is improved.The independent tuning of single Fano resonance peaks and simultaneous modulation of multiple Fano resonances are realized by studying the relationship between structural parameters and resonance spectra.The nano-silver disk in the ice cream-shaped resonator is split from the center,a new F-P resonator is constructed inside,and the secondary resonance is obtained.The triple Fano resonance can realize the independent tuning of the single wave peak and the simultaneous tuning of the multiple wave peak.On this basis,Fano resonance differential sensing characteristics are studied,which brings a new idea for the design of the anti-disturbance micro-nano sensor.