Optical absorption tunability and local electric field distribution of gold-dielectric-silver three-layered cylindrical nanotube*

Abstract

The effects of inner nanowire radius, shell thickness, the dielectric functions of middle layer and surrounding medium on localized surface plasmon resonance (LSPR) of gold-dielectric-silver nanotube are studied based on the quasi-staticapproximation. Theoretical calculation results show that LSPR of gold-dielectric-silver nanotube and LSPR numbers can bewell optimized by adjusting its geometrical parameters. The longer wavelength of | ω − − 〉 mode takes place a distinct red-shift with increasing the inner nanowire radius and the thickness of middle dielectric layer,while a blue-shift with increasing outer nanotube thickness. The physical mechanisms are explained based on the plasmon hybridization theory, induced charges and phase retardation. In addition, the effects of middle dielectric function and surrounding medium on LSPR, and the local electric field factor are also reported. Our study provides the potential appications of gold-dielectric-silver nanotube in biological tissues, sensor and related regions.