Enhanced surface plasmon resonance based on the silver nanoshells connected by the nanobars

Enhanced surface plasmon resonances in a silvershell nanocylindrical pair connected by a different type of nanobar that interacts with incident plane wave of transverse magnetic polarization are simulated by use of the finite element method. Arrays of silver nanoshells connected by silver nanobars are also investigated. The proposed structure exhibits a red-shifted localized surface plasmon that can be tuned over an extended wavelength range by varying the width of the nanobar and the dielectric constant in dielectric holes (DHs). The increase in the scattering cross sections is attributed to the effects of surface plasmon on the nanobar surface and a larger effective size of DH that is filled with a higher refractive medium. The predictive character of these calculations allows one to tailor the shape of the nanoparticle to achieve excitation spectra on demand with a controlled field enhancement. (C) 2009 Optical Society of America