Research Of Fano Resonances And Polarization State-based Refractive Index Sensing In Nanorod Polymer

The incident field energy can be localized on the surface nanostructures and break though the diffraction limit of light, because of the localized surface plasmon resonance of metal nanoparticle. In recent years, it has received more and more attention from researchers. In which the metal nanorod shape having an anisotropic and longitudinal resonance is very sensitive to change the aspect ratioa, meanwhile the preparation of metal nanorod with good controllability(chemical synthesis, suface etching,etc), people paid special attention to its study. Metal nanoparticles polymer through the arrangement of on the space design to form mode hybrid by near-field coupling. It produces super-radiation bright modes and weak radiation dark modes. Bright modes and dark modes destructive interferences ofen lead to the formation of Fano resonances effect.For the Fano resonances in the surface plasmon system, not only the radiation damping of nanostructure can be effectively reduced to make the spectrum more fine, but also produce stronger electromagnetic field enhancement. As the result,the Fano resonances in the metal nanostructure are useful for biosensing and so on. Although the use of Fano resonances system can reduce the radiative decay,however, due to the presence of non-radiation loss in metal nanostructures,reducing the sensitivity of the biosensor applications.The paper fist is designed polymer structure of the metal nanorods, the use of coupling between the nanoparticles resulted in Fano resonances effect.We also propose a polarization state-based refractive index sensing methods,improved sesor sensitivity. The main work includes:(1)We study the double fano resonance phenomenon in the composite structure omposed of nanorod and two of dipole nanoantennas, analysis the extinction spectrum, near-field enhancement and charge distributions and discuss the forming reasons of Fano resonances. In addition, the modulation depth and spectrum position of the Fano resonances can be tuned by varitions of structural parameters. The gold nanorod composite structure can be used for the optimal design of the nano electronic devices.(2) This study provides a polarization state-based refractive index sensing method using plasmonic nanostructures to improve the sensing performance.Analysis the reciprocal of ellipticity for transmitted field in L-shape nanorodd and nanorod dimers. Sharp resonances with line widths is very narrow and value of the figure of merit exceeding 1700 is achieved. As well as, analysis the bulk refractive index sensitivity and surface sensitivity. Compared to the method of using polarization of ferromagnetic nanoparticles, plasmonic nanostructures of the sensor performance is vastly improved...