由金属纳米盘和金属基板上的介电间隔层组成的超材料中的环形偶极激发

Toroidal Dipolar Excitation in Metamaterials Consisting of Metal nanodisks and a Dielectrc Spacer on Metal Substrate.

作者信息

Tang Chaojun, Yan Bo, Wang Qiugu, Chen Jing, Yan Zhendong, Liu Fanxin, Chen Naibo, Sui Chenghua

机构信息

Center for Optics & Optoelectronics Research and Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China.

Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa, 50011, USA.

出版信息

Sci Rep. 2017 Apr 3;7(1):582. doi: 10.1038/s41598-017-00708-5.

DOI:10.1038/s41598-017-00708-5

PMID:28373721

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5429647/

Abstract

We have investigated numerically toroidal dipolar excitation at optical frequency in metamaterials whose unit cell consists of three identical Ag nanodisks and a SiO spacer on Ag substrate. The near-field plasmon hybridization between individual Ag nanodisks and substrate forms three magnetic dipolar resonances, at normal incidence of plane electromagnetic waves. The strong coupling among three magnetic dipolar resonances leads to the toroidal dipolar excitation, when space-inversion symmetry is broke along the polarization direction of incident light. The influences of some geometrical parameters on the resonance frequency and the excitation strength of toroidal dipolar mode are studied in detail. The radiated power from toroidal dipole is also compared with that from conventional electric and magnetic multipoles.

摘要

我们对超材料中光频下的环形偶极子激发进行了数值研究，该超材料的单元胞由三个相同的银纳米盘和银衬底上的一个二氧化硅间隔层组成。在平面电磁波垂直入射时，单个银纳米盘与衬底之间的近场等离子体杂化形成了三个磁偶极子共振。当空间反演对称性沿入射光的偏振方向被打破时，三个磁偶极子共振之间的强耦合导致了环形偶极子激发。详细研究了一些几何参数对环形偶极子模式的共振频率和激发强度的影响。还将环形偶极子的辐射功率与传统电多极子和磁多极子的辐射功率进行了比较。