Chung H Y, Leung P T, Tsai D P
Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
J Chem Phys. 2009 Sep 28;131(12):124122. doi: 10.1063/1.3236528.
We present an approach alternative to the hybridization model for the treatment of the coupled interfacial plasmon modes in spheroidal metallic nanoshells. Rather than formulating the problem from the Lagrangian dynamics of the free electronic fluid, we adopt an effective medium approach together with the uniqueness of the solutions to electromagnetic boundary value problem, from which the polarizability of the shells can then be systematically and efficiently derived; and the resonance frequencies for the coupled modes can be obtained from the poles in the polarizability. This approach can treat confocal nanoshells with different geometries for the spheroidal cavity and external surface and allow for a natural extension to incorporate corrections from the finiteness of the optical wavelength which are important for nanoparticles of larger sizes. This thus surpasses the hybridization model which is limited to incorporate only the electrostatic Coulomb interaction between the uncoupled plasmons. Numerical results will be provided for different nanoshell systems, and for the illustration of the various geometric and dynamic effects from our model.
我们提出了一种不同于杂交模型的方法，用于处理球形金属纳米壳中耦合界面等离子体激元模式。我们不是从自由电子流体的拉格朗日动力学来阐述问题，而是采用有效介质方法以及电磁边界值问题解的唯一性，由此可以系统且高效地推导出壳层的极化率；耦合模式的共振频率可从极化率的极点获得。这种方法可以处理具有不同几何形状的共焦纳米壳，包括球形腔和外表面的几何形状，并自然地扩展以纳入光学波长有限性带来的修正，这对于较大尺寸的纳米颗粒很重要。因此，这超越了杂交模型，后者仅限于纳入未耦合等离子体激元之间的静电库仑相互作用。将给出不同纳米壳系统的数值结果，以说明我们模型的各种几何和动态效应。
