3D-FEM analysis of SPP excitation through nanoholes in asymmetric metal-insulator-metal structure at tip of circular truncated conical fiber
3D-FEM analysis of SPP excitation through nanoholes in asymmetric metal-insulator-metal structure at tip of circular truncated conical fiber
复制标题
通过圆形截锥形光纤尖端不对称金属-绝缘体-金属结构中的纳米孔进行 SPP 激发的 3D-FEM 分析
DOI：
10.1117/12.2060641
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Motohiro Nakano
中科院分区：
文献类型：
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作者：
Yasushi Oshikane;Kensuke Murai;Motohiro Nakano
利用基于有限元法的三维有限元软件包，对可见光在光纤中单模传输激发的表面等离子体激元进行了三维电磁分析。光纤的端部通过湿法刻蚀工艺形成为圆锥形，并被光纤化以形成具有直径为几微米的平坦圆形表面的圆形截锥形状。平坦端覆盖有三层非对称金属绝缘体-金属结构，分别为薄金属层（M1）、厚绝缘体层（I）和厚金属层（M2）。最外层的M2层具有Fibed纳米孔，以将光纤末端的光波有效地转换为SPP，并且在M2层的表面上将产生明亮的微小点光源。在这项研究中，三维有限元模型包括MIM结构和收缩的光纤尖端涂有金属薄膜已被设计和数值分析。通过将理想电导体和理想磁导体应用于包含旋转轴的平面，有限元模型具有四分之一的圆形截头圆锥形状。有限元分析分两步进行。在第一步中，执行FEM模式分析以获得对应于SM在光纤中的传播的解。第二层次的行动是在整个模型中的EM场的有限元分析，以找到一个固定的解决方案与模式分析的解决方案。本文将介绍这种光纤尖端的几种试制产品的实验结果，并讨论表面等离子体的激发、传播和聚焦特性随波长的变化。
3D-electromagnetic (EM) analysis of surface plasmon polaritons (SPPs) excited by a single-mode (SM) propagation of visible lightwave in an optical fiber has been studied with a 3D-FEM package based on a finite element method. End of the fiber is formed to be a circular cone by wet etching process, and is FIBed to make a circular truncated conical shape with a flat circular surface a few micrometers in diameter. The flat end is covered with three layers of asymmetric metalinsulator- metal structure, thin metallic layer (M1), thick insulator layer (I), and thick metallic layer (M2), respectively. The outermost M2 layer has FIBed nanoholes to convert light waves at the extremity of the fiber into SPPs efficiently, and a bright tiny point light source will be generated on the surface of the M2 layer. In this study, the 3D-FEM models consists of both the MIM structure and the shrinking optical fiber tip coated with a metallic thin film has been designed and analyzed numerically. By applying perfect electric conductor and perfect magnetic conductor to planes containing the axis of rotation, the FEM model has a quarter of the circular truncated conical shape. The FEM analysis is formed in two steps. At the first step, a FEM mode analysis is performed to obtain a solution corresponding to the SM propagation in the fiber. The second level of action is the FEM analysis of EM field in the whole of model to find a stationary solution with the solution of mode analysis. Characteristic of wavelength-dependent excitation, propagation, and focusing of the SPPs will be presented with several experimental results of trial products of the fiber tip.