Research On Sensing And Slow Light Characteristics Of Fano Resonance Based On MIM Waveguide

Surface Plasmon Polaritons(SPPs)is able to achieve nano-scale control of light,breaking through the diffraction limit of traditional optics while holding a strong local field enhancement effect,which attracts high attention from researchers.Metal-Insulator-Metal(MIM)waveguide structure is a typical SPPs waveguide structure.Due to strong modular field limitation,little transmission loss and long electromagnetic wave transmission distance,it has a great constraint on SPPs mode,which is believed to have a promising future in the field of micro-nano optical devices and integrated circuits.This paper presents multiple new structures of MIM waveguide coupled resonator.It studies and analyzes the Fano resonance effect generated by the structures,and explores the effect of the change in the structural parameters on the sensing and slow light characteristics.The structure has been improved and expanded to achieve independent tuning function.The specific research contents are as follows:1.It presents a new SPPs structure based on a metal slit in a MIM waveguide which is coupled with a connected rectangular semicircular ring.Due to the interference coupling between the wide continuous state of a straight waveguide with a metal slit and the narrow discrete state of a connected rectangular semicircular cavity,two sharp Fano resonance shapes are generated in the transmission spectrum of the structure.The maximum sensitivity of the proposed structure as a refractive index sensor is 1000 nm/RIU,and the optimized FOM is 4.37×104.As a temperature sensor,the maximum sensitivity is 0.27nm/?,and the FOM is 2.83.As a slow-light device,the maximum group delay can be 0.215ps,and the maximum group index is 81.2.It proposes two-sided coupled connected rectangular semicircular cavity structure and teethed connected rectangular semicircular cavity structure.These structures achieve the independent tuning function of a Fano resonance peak.3.A MIM SPPs structure is improved to produce a triple Fano resonance profile in the transmission spectrum.The sensitivity of the new structure as a refractive index sensor achieves 1200nm/RIU,the FOM is 4.71 ×104.As a slow-light device,the group delay is 0.339ps and the group index is 127.3.