Effect of Geometrical Parameters on Local Electric Field Enhancement of Bimetallic Three-Layered Nanotubes by Using Quasi-static Theory

Abstract

Due to the plasmon hybridization between nanowire and outer nanotube, the geometrical parameters of nanotube take great effect on absorption cross section and local electric field enhancement. In this paper, we study the effects of the inner nanowire radius, shell thickness, middle dielectric functions and surrounding medium functions on absorption cross section and local electric field enhancement of bimetallic three-layered nanotubes, gold-dielectric-silver (GDS) nanotube and silver-dielectric-gold (SDG) nanotube in detail based on quasi-static theory. The results show that the thickness of outer nanotube plays a more role to tune local surface plasmon resonance (LSPR) than that of inner nanowire, whereas a better LSPR could be obtained with a higher surrounding dielectric function. In addition, the local electric field enhancement is also investigated.The maximum local electric field enhancement could be obtained with smaller thickness of dielectric layer and higher surrounding dielectric function. Our study provides a way to analyze optical properties of GDS and SDG nanotube and also broaden their applications in sensor and optical data storage.