Numerical modeling of plasmon-assisted nanotube sensors of the host-medium refractive index

We consider numerical modeling of the sensing characteristics of circular nanotubes made of gold and silver. The tubes are placed into a homogeneous medium, the refractive index of which is to be determined, and illuminated by the H-polarized visible light. The scattering, absorption and extinction cross-sections are calculated and display host-medium dependent hybrid localized surface-plasmon (LSP) resonances of the dipole and quadrupole type. The sensitivities and the figure-of-merit values of these LSP resonances are computed and compared for the infinite and finite thickness of the analyte layer.