Resonance Of I-shaped Metamaterials

The metamaterials is a kind of new composite materials designed by artificial design,which have very high permeability and dielectric constant.Under the irradiation of incident light,the metamaterials with I metal structure has a unique electromagnetic properties,which is caused by the excitation of the surface plasmon resonance(SPR)phenomenon on the surface of the metamaterials metal.In the study of the resonance of the metamaterials with I metal structure.When the metal surface structural units are changed,the special reflection phenomenon appears.Under the irradiation of polarized light,the different surface plasmon resonance coupling modes are excited,leading to the phenomenon of electromagnetic induction reflection.In this thesis,symmetry and asymmetry strucuteres are considered.The reflected spectra are investigated through Finite Difference of time domain(FDTD).TThe main tasks are as follows:(1)The theory mode deduction and analysis.One unit of structure consists of two horizontal slits and a vertical slit.When the polarized light is incident on the structure surface,the SP resonance in the vertical slit is excited.Then the fields is coupled into the horizontal slits,exciting the SP resonances in the the horizontal slits.the resonant conditions in the every part of the structure are obtained,which lead different resonance modes.(2)The reflection of I-shaped metamaterial is investigated through FDTD.The electromagnetic induced reflection mode(EIR)is stimulated in the I-shaped metamaterial,and the physical mechanisms of the reflection modes are analyzed.When the symmetry of the structure is broken and the slit length increases,two modes appear,respectively.Through analyzing near fields and the properties of reflected modes,it is believed,the degenerate mode splits when the symmetry of structure is broken and high-order mode appears with the slit length increasing.The couplings between surface plasmon resonance modes at different positions of structure cangenerate five special modes.