Hybrid plasmon resonances in the scattering and absorption of light by a circular silver nanotube

We study the scattering and absorption of an H-polarized plane electromagnetic wave by a silver nanotube, in the visible range of wavelengths. The tube is assumed to have circular cross-section. The analytical solution of the wave-scattering problem is obtained in classical manner, using the separation of variables in the polar coordinates. In computations, we use the Johnson and Christy data for the silver refractive index. The computed spectra of the total scattering cross-section and the absorption cross-section display two main surface-plasmon resonances, of the dipole and quadrupole type. This data can be useful for the design of nanotube-based sensors of the changes in refractive index of host medium.