Research And Application Of Multiple Fano Resonances Based Of Coupled T-type Cavity

With the theory of photonic integration and its manufacturing process developing rapidly,optical integrated circuit is also moving towards higher integration,the high integration means that the functional devices more integrated into a single chip,optoelectronic devices is small enough.Surface plasmon polaritons(SPPs)has become an important part in the field of nano photonics,it is formed by conduction electrons interacting with electromagnetic radiation,exsiting on the metal-dielectric interfaces,a type of electromagnetic mode.It can not only overcome the diffraction limit,but also reduce the energy attenuation in the process of the spread,caused by metal absorption.Based on metal-insulator-metal(MIM)surface plasmons waveguide technology,many optoelectronic devices is designed,such as: optical splitter,resonators,sensors and so on.Four novel MIM waveguide structures consists of T-type cavity and wavegude are proposed in the paper.For exploring the response characteristics of these optical waveguide structures,we analyze them by finite element method(FEM)of COMSOL Multiphysics software.Firstly,the simulation results show the double Fano resonances for the positive T-type cavity structure,and the resonant wavelength can be easily tuned by changing the length and the height of the T-type cavity.The structure would be helpful for designing the nano-sensor with a sensitivity of 1620 nm/RIU(Refractive Index Unit,RIU)and the figure of merit of5.4×10~4.By inverting the T-type cavity,multiple Fano resonances are observed in the waveguide with a sensitivity of 1560 nm/RIU and the figure of merit of 9.37×10~4,and the sensitivity of three resonances are different,one of them can be adjusted,independent of the others.,which may have applications in the spectral splitter.The third waveguide structure is the double T-type cavity structure,the simulation results show the multiple Fano resonances,that provides extension for the more complex splitter.Finally,the simulation results show the single Fano resonances for the embedded T-type cavity structure,and it may be designing the nano-sensor.