Gerislioglu Burak, Dong Liangliang, Ahmadivand Arash, Hu Huatian, Nordlander Peter, Halas Naomi J
The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
Nano Lett. 2020 Mar 11;20(3):2087-2093. doi: 10.1021/acs.nanolett.0c00075. Epub 2020 Feb 4.
Dimers, two closely spaced metallic nanostructures, are one of the primary nanoscale geometries in plasmonics, supporting high local field enhancements in their interparticle junction under excitation of their hybridized "bonding" plasmon. However, when a dimer is fabricated on a metallic substrate, its characteristics are changed profoundly. Here we examine the properties of a Au dimer on a Au substrate. This structure supports a bright "bonding" dimer plasmon, screened by the metal, and a lower energy magnetic charge transfer plasmon. Changing the dielectric environment of the dimer-on-film structure reveals a broad family of higher-order hybrid plasmons in the visible region of the spectrum. Both of the localized surface plasmons resonances (LSPR) of the individual dimer-on-film structures as well as their collective surface lattice resonances (SLR) show a highly sensitive refractive index sensing response. Implementation of such all-metal magnetic-resonant nanostructures offers a promising route to achieve higher-performance LSPR- and SLR-based plasmonic sensors.
二聚体，即两个紧密间隔的金属纳米结构，是等离激元学中的主要纳米级几何结构之一，在其杂化“键合”等离激元的激发下，在其粒子间结处支持高局部场增强。然而，当在金属基底上制造二聚体时，其特性会发生深刻变化。在这里，我们研究了金基底上金二聚体的性质。这种结构支持一种明亮的“键合”二聚体等离激元，由金属屏蔽，以及一种能量较低的磁荷转移等离激元。改变薄膜上二聚体结构的介电环境会在光谱的可见光区域揭示出一大类高阶混合等离激元。单个薄膜上二聚体结构的局域表面等离激元共振（LSPR）及其集体表面晶格共振（SLR）都显示出高度灵敏的折射率传感响应。实现这种全金属磁共振纳米结构为实现基于LSPR和SLR的高性能等离激元传感器提供了一条有前景的途径。
