Panaretos Anastasios H, Werner Douglas H
Opt Express. 2015 Feb 23;23(4):4459-71. doi: 10.1364/OE.23.004459.
In this paper we demonstrate the feasibility of using multiport network theory to describe the admittance properties of a longitudinally loaded plasmonic nanorod antenna. Our analysis reveals that if the appropriate terminal ports are defined across the nanorod geometry then the corresponding voltage and current quantities can be probed and thus it becomes feasible to extract the admittance matrix of the structure. Furthermore, it is demonstrated that by utilizing cylindrical dielectric waveguide theory, closed form expressions can be derived that uniquely characterize the loading material in terms of its admittance. The combination of the admittance matrix information along with the load admittance expressions provides an effective methodology for computing the nanorod's input admittance/impedance for arbitrary loading scenarios. This is important because the admittance resonances are associated with the structure's scattering peaks which are excited by a plane wave polarized parallel to its long dimension. Subsequently, the proposed approach provides a fast and computationally efficient circuit-based methodology to predict and custom engineer the scattering properties of a loaded plasmonic nanorod without having to rely on repetitive lengthy full wave simulations.
在本文中，我们展示了使用多端口网络理论来描述纵向加载的等离子体纳米棒天线导纳特性的可行性。我们的分析表明，如果在纳米棒几何结构上定义适当的终端端口，那么相应的电压和电流量就可以被探测到，从而提取该结构的导纳矩阵就变得可行。此外，结果表明，通过利用圆柱介质波导理论，可以推导出封闭形式的表达式，这些表达式可以根据其导纳唯一地表征加载材料。导纳矩阵信息与负载导纳表达式的结合，为计算任意加载情况下纳米棒的输入导纳/阻抗提供了一种有效的方法。这很重要，因为导纳共振与结构的散射峰相关，这些散射峰由平行于其长轴方向极化的平面波激发。随后，所提出的方法提供了一种快速且计算效率高的基于电路的方法，无需依赖重复冗长的全波模拟即可预测和定制设计加载的等离子体纳米棒的散射特性。
