Mode Properties And Fluorescence Emission Mediation Of Metal-Dielectric-Metal Nanoantenna Array

The surface plasmon polarization(SPP)has a strong local enhancement characteristic for electromagnetic field.When it interacts with the fluorescent molecule,it can increase the electron absorption and attenuation rate,which leads to the improvement of fluorescence emission efficiency.Therefore,surface plasmon polarization is expected to become an effective means to improve the performance of light-emitting diodes(LEDs),laser diodes(LDs),solar cells and other devices,and have potential application value in biological imaging,optical sensing and nanophotonics.In recent years,metal nanostructures have attracted much attention because of their support for many kinds of surface plasmon polarization resonance modes.By constructing metal nanostructures,the fluorescence radiation can be regulated by using the supported surface plasmon polarization resonance modes.A metal-dielectric-metal rectangular nanoantenna array is designed and its mode properties and mediation for fluorescence emission are analyzed.The transmission spectrum,reflection spectrum and electric field distribution of the structure are simulated by finite-difference time-domain(FDTD)method.The mode properties of the locallized surface plasmon(LSP)mode and magnetic plasmon polaritons(MPP)mode and the mode changes modulated by excitation light polarization are analyzed.Further,A dipole source is placed in the dielectric layer to simulate the emission of fluorescent molecule regulated by the structure.The main research contents of this thesis are as follows:1.Starting from the electromagnetic characteristics of a single particle,the electric polarizability tensor and magnetic polarizability tensor curves of the particles can be obtained by measuring the far-field scattering field of the nanoparticles to two plane waves with opposite incident directions.The electric resonance and magnetic resonance positions of the particles were obtained by the polarizability tensor curve.By changing the structural parameters of the particles,the resonant position of a single metal-media-metal nanantenna array can be regulated.2.Single metal-dielectric-metal nanoparticles are arranged into a metal-dielectric-metal nanoantenna array.The electromagnetic mode properties and the tunability of the resonant positions supported in MDM nanoantenna array are analyzed by using FDTD Solutions software.The response of the position of the electromagnetic resonance to the changing of the structural parameters is studied,and the polarization dependence of the incident light at the resonant position of the structure is proved.3.The dipole source was placed in the medium layer of the structure,and the regulation of the structure on the luminescence process was simulated.It is proved that the radiation and non-radiation attenuation rate,quantum efficiency,polarization properties and radiation direction of the fluorescence molecules can be effectively regulated by the structure,and the emission spectrum can be tuned in a certain range by changing the polarization of the excited light.Innovation points of this thesis:1.MDM nanantenna array is designed and the mode characteristics under different structure parameters is studied systematically.It is proved that the structure only supports LSP mode and MPP mode in the asymmetric medium background with a period much smaller than the wavelength.The mode position is not affected by the structure period,and the position of the electromagnetic resonance can be tuned by changing the polarization of the incident light.2.Based on the light localization and the resonance position tunability of the MDM nanoantenna array,we use the method of simulation proving that when flourescent molecule is placed in dielectric layer,the radiation and no-radiation attenuation rate,quantum efficiency,polarization properties and emossion directional properties of the molecule will be regulated by the resonance modes of the structure.The simulation results have a good guiding significance for the relevant experiments and provide a theoretical basis for the regulation of luminescence process and the realization of nanometer laser.