Geometrical Tunability and Local Electric Field Distribution of Gold-dielectric-silver three-layered Cylindrical Nanotube

In this paper, the effects of inner core radius, shell thickness, the dielectric function of middle nanoshell and surrounding medium on localized surface plasmon resonance (LSPR) of gold-dielectric-silver nanotube are studied based on the quasi-static approximation. Theoretical calculation results show that LSPR of gold-dielectric-silver nanotube and LSPR numbers can be well optimized by tuning the geometrical parameters. The longer wavelength of |ω−⟩ mode takes place a distinct red-shift with an increase in the inner core radius and the thickness of middle dielectric layer, while a blue-shift with increasing outer shell thickness. The physical mechanisms are investigated based on induced charges, plasmon hybridization theory and phase retardation. In addition, the effect of middle dielectric function and surrounding medium on LSPR , the local electric field distribution are also reported. Our study provides a way to analyze and broaden the applications of gold-dielectric-silver nanotube.