Local Dielectric Environment Dependent Local Electric Field Enhancement in Double Concentric Silver Nanotubes

The local dielectric environment dependent local field enhancement properties in double concentric silver nanotubes have been obtained by using the plasmon hybridization method and quasi-static calculation. Because of the inserted silver nanotube, the geometrical parameter controlled intertube coupling greatly improves the tunability of the local dielectric dependent enhancement of local electric field. In the inner dielectric core, the most intense local field factor peak corresponds to the |ω_–⁺⟩ plasmon mode, and the major local field factor peak usually changes nonmonotonously as the inner core or spacer layer dielectric is increased. The maximum local field could be obtained by fine-tuning the local dielectric constant in the double tubes with thick inner and outer tube thickness. In the dielectric spacer layer, the most intense local field factor peak corresponds to the |ω_–^–⟩ plasmon mode. The intense local field could be obtained with small spacer layer dielectric constant and reaches the maximum value when the double tube has thick inner and outer tube thickness. This inner core and spacer layer dielectric dependent local field enhancement provides the potential application of the real time tubular nanosensor based on local field induced fluorescence enhancement and surface-enhanced Raman scattering (SERS).