Zhuo Xiaolu, Li Shasha, Li Nannan, Cheng Xizhe, Lai Yunhe, Wang Jianfang
Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 Donostia-San Sebastián, Spain.
Nanoscale. 2022 Jun 16;14(23):8362-8373. doi: 10.1039/d2nr01402e.
Optical antenna effects endow plasmonic nanoparticles with the capability to enhance and control various types of light-matter interaction. Most reported plasmonic systems can be regarded as single-channel nanoantennas, which rely only on a bright dipole plasmon mode for energy exchange between near- and far-field. Herein we demonstrate a dual-channel plasmonic system that can separate the excitation and emission processes into two energy exchange pathways mediated by the different plasmon modes, offering a higher degree of freedom for the manipulation of light-matter interaction. Our system, consisting of high-aspect-ratio Ag nanorods and Si substrates, can support a series of bright and dark plasmon modes with distinct near- and far-field properties and generate relatively intensive local field enhancement in the gap region. As a proof-of-principle, we take plasmon-enhanced fluorescence of dye molecules as an example to reveal the energy exchange mechanism in the dual-channel plasmonic system. Such a system is potentially also useful for manipulating other types of light-matter interaction. Our work represents a step toward the utilization of a broader class of plasmon resonance for the development of optical antennas and various on-chip nanophotonic components.
光学天线效应赋予等离子体纳米颗粒增强和控制各种光与物质相互作用的能力。大多数已报道的等离子体系统可被视为单通道纳米天线，其仅依赖于明亮的偶极子等离子体模式进行近场和远场之间的能量交换。在此，我们展示了一种双通道等离子体系统，该系统可将激发和发射过程分离为两个由不同等离子体模式介导的能量交换途径，为光与物质相互作用的操控提供了更高的自由度。我们的系统由高纵横比的银纳米棒和硅衬底组成，能够支持一系列具有不同近场和远场特性的明亮和暗等离子体模式，并在间隙区域产生相对强烈的局部场增强。作为原理验证，我们以染料分子的等离子体增强荧光为例，揭示双通道等离子体系统中的能量交换机制。这样的系统对于操控其他类型的光与物质相互作用也可能具有潜在用途。我们的工作代表了朝着利用更广泛的等离子体共振来开发光学天线和各种片上纳米光子组件迈出的一步。
