Guan Fuxin, Sun Shulin, Ma Shaojie, Fang Zhening, Zhu Baocheng, Li Xin, He Qiong, Xiao Shiyi, Zhou Lei
Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, People's Republic of China.
J Phys Condens Matter. 2018 Mar 21;30(11):114002. doi: 10.1088/1361-648X/aaad2a.
Although surface plasmon polaritons (SPPs) have been intensively studied in past years, the transmission/reflection properties of SPPs at an interface between two plasmonic media are still not fully understood. In this article, we employ a mode expansion method (MEM) to systematically study such a problem based on a model system jointing two superlattices, each consisting of a periodic stacking of dielectric and plasmonic slabs with different material properties. Such a generic model can represent two widely used plasmonic structures (i.e. interfaces between two single dielectric/metal systems or between two metal-insulator-metal waveguides) under certain conditions. Our MEM calculations, in excellent agreement with full-wave simulations, uncover the rich physics behind the SPP reflections at generic plasmonic interfaces. In particular, we successfully derive from the MEM several analytical formulas that can quantitatively describe the SPP reflections at different plasmonic interfaces, and show that our formulas exhibit wider applicable regions than previously proposed empirical ones.
尽管表面等离激元极化激元（SPPs）在过去几年中得到了深入研究，但在两种等离子体介质界面处SPPs的传输/反射特性仍未得到充分理解。在本文中，我们采用模式展开法（MEM），基于一个由两个超晶格连接而成的模型系统，系统地研究这一问题，每个超晶格由具有不同材料特性的电介质和等离子体平板的周期性堆叠组成。在某些条件下，这样一个通用模型可以代表两种广泛使用的等离子体结构（即两个单电介质/金属系统之间或两个金属-绝缘体-金属波导之间的界面）。我们的MEM计算与全波模拟结果高度吻合，揭示了通用等离子体界面处SPP反射背后丰富的物理现象。特别是，我们成功地从MEM中推导出几个解析公式，这些公式可以定量描述不同等离子体界面处的SPP反射，并表明我们的公式比先前提出的经验公式具有更广泛的适用范围。
