金纳米球壳光学吸收的Mie理论分析

基于Mie散射理论研究了金壳厚度变化、内核尺寸变化及内核介质变化下金纳米球壳的吸收光谱.研究发现，随着金壳厚度的增加，颗粒光学吸收增加到最大值后逐渐降低；随着内核尺寸逐渐增加，金壳颗粒的光学吸收最大值逐渐减小.此外，还发现随着内核介电常数的增大，颗粒的光学吸收逐渐减弱，当内核为空心时，吸收最强.利用等离激元杂化理论及自由电子和振荡电子变化的竞争机制对上述现象进行了理论分析.关键词：金纳米球壳等离激元共振吸收光谱

Study on the optical absorption of gold nanoshells by Mie theory

The variations of optical absorption of gold nanoshells with the shell thickness, size of the core, and core dielectric constant have been investigated by means of Mie theory. It was found that with the increase in the thickness of the shell, the strength of absorption peak increases first and then decreases. We also observed that with increasing core size the maximum optical absorption of the particles decreases. Furthermore, the increase of the core dielectric constant reduces the strength of absorption peak and the hollow gold nanoshells have the maximum optical absorption. We ascribe the change of the absorption peaks to the plasmon hybridization and the competition between the variations of conduction and oscillation electrons.