Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden.
ACS Nano. 2017 Apr 25;11(4):4265-4274. doi: 10.1021/acsnano.7b01318. Epub 2017 Apr 7.
Synthetic three-dimensional (3D) nanoarchitectures are providing more control over light-matter interactions and rapidly progressing photonic-based technology. These applications often utilize the strong synergy between electromagnetic fields and surface plasmons (SPs) in metallic nanostructures. However, many of the SP interactions hosted by complex 3D nanostructures are poorly understood because they involve dark hybridized states that are typically undetectable with far-field optical spectroscopy. Here, we use experimental and theoretical electron energy loss spectroscopy to elucidate dark SPs and their interactions in layered metal-insulator-metal disc nanostructures. We go beyond the established dipole SP hybridization analysis by measuring breathing and multipolar SP hybridization. In addition, we reveal multidimensional SP hybridization that simultaneously utilizes in-plane and out-of-plane SP coupling. Near-field classic electrodynamics calculations provide excellent agreement with all experiments. These results advance the fundamental understanding of SP hybridization in 3D nanostructures and provide avenues to further tune the interaction between electromagnetic fields and matter.
合成的三维（3D）纳米结构为控制光与物质相互作用提供了更多的手段，也推动了基于光子的技术快速发展。这些应用通常利用电磁场与金属纳米结构中的表面等离激元（SPs）之间的强协同作用。然而，由于涉及到通常无法通过远场光学光谱检测到的暗杂化态，许多由复杂 3D 纳米结构承载的 SP 相互作用仍未被很好地理解。在这里，我们使用实验和理论电子能量损失光谱来阐明分层金属-绝缘体-金属盘状纳米结构中的暗 SPs 及其相互作用。我们通过测量呼吸模式和多极 SP 杂化超越了已建立的偶极 SP 杂化分析。此外，我们揭示了同时利用平面内和平面外 SP 耦合的多维 SP 杂化。近场经典电动力学计算与所有实验结果吻合得非常好。这些结果推进了对 3D 纳米结构中 SP 杂化的基本理解，并为进一步调整电磁场与物质之间的相互作用提供了途径。
