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.

由于纳米线与外层纳米管之间的等离激元杂化，纳米管的几何参数对吸收截面和局部电场增强有很大影响。在本文中，我们研究了内纳米线半径、壳厚度、中间介电函数和周围介质函数对双金属三层纳米管、金-电介质-银 (GDS) 纳米管和纳米管的吸收截面和局部电场增强的影响。基于准静态理论详细介绍了银-电介质-金 (SDG) 纳米管。结果表明，与内部纳米线相比，外部纳米管的厚度对调节局部表面等离子体共振 (LSPR) 起着更大的作用，而较高的周围介电函数可以获得更好的 LSPR。此外，还研究了局部电场增强。较小的介电层厚度和较高的周围介电函数可以获得最大的局部电场增强。我们的研究提供了一种分析 GDS 和 SDG 纳米管光学特性的方法，并拓宽了它们在传感器和光学数据存储中的应用。