Plasmon-Assisted Scattering of Light by a Circular Silver Nanowire with Concentric Dielectric Coating

We study the scattering and absorption of an H-polarized plane electromagnetic wave by a silver nanowire, in the visible range of wavelengths. The wire is assumed to have circular cross-section and coated with a concentric circular dielectric layer. The analytical solution of the wave-scattering problem is obtained in classical manner, using the separation of variables and the transfer-matrix method in polar coordinates. In computations, we use the accurate data of Johnson and Christy for the complex refractive index of silver. If the coating thickness and its dielectric permittivity become larger, the computed spectra of the total scattering cross-section (TSCS) and the absorption cross-section (ACS) display, at first, a shift of broad surface-plasmon resonances to the red side and then their hybridization with the modes of the coating. This data can be useful for the design of nanowire-based sensors where the analyzed substance makes a finite-thickness layer on the wire.