Smith C L C, Stenger N, Kristensen A, Mortensen N A, Bozhevolnyi S I
Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
Nanoscale. 2015 Jun 7;7(21):9355-86. doi: 10.1039/c5nr01282a.
Tapered metallic grooves have been shown to support plasmons - electromagnetically coupled oscillations of free electrons at metal-dielectric interfaces - across a variety of configurations and V-like profiles. Such plasmons may be divided into two categories: gap-surface plasmons (GSPs) that are confined laterally between the tapered groove sidewalls and propagate either along the groove axis or normal to the planar surface, and channeled plasmon polaritons (CPPs) that occupy the tapered groove profile and propagate exclusively along the groove axis. Both GSPs and CPPs exhibit an assortment of unique properties that are highly suited to a broad range of cutting-edge nanoplasmonic technologies, including ultracompact photonic circuits, quantum-optics components, enhanced lab-on-a-chip devices, efficient light-absorbing surfaces and advanced optical filters, while additionally affording a niche platform to explore the fundamental science of plasmon excitations and their interactions. In this Review, we provide a research status update of plasmons in tapered grooves, starting with a presentation of the theory and important features of GSPs and CPPs, and follow with an overview of the broad range of applications they enable or improve. We cover the techniques that can fabricate tapered groove structures, in particular highlighting wafer-scale production methods, and outline the various photon- and electron-based approaches that can be used to launch and study GSPs and CPPs. We conclude with a discussion of the challenges that remain for further developing plasmonic tapered-groove devices, and consider the future directions offered by this select yet potentially far-reaching topic area.
锥形金属凹槽已被证明能够在各种结构和V形轮廓中支持表面等离子体激元——金属-电介质界面处自由电子的电磁耦合振荡。这种表面等离子体激元可分为两类：间隙表面等离子体激元（GSPs），其在横向被限制在锥形凹槽侧壁之间，可沿凹槽轴线或垂直于平面表面传播；以及通道等离子体激元（CPPs），其占据锥形凹槽轮廓并仅沿凹槽轴线传播。GSPs和CPPs都展现出一系列独特的性质，这些性质非常适合广泛的前沿纳米等离子体技术，包括超紧凑光子电路、量子光学元件、增强型芯片实验室设备、高效光吸收表面和先进光学滤波器，同时还提供了一个独特的平台来探索表面等离子体激元激发及其相互作用的基础科学。在本综述中，我们提供了锥形凹槽中表面等离子体激元的研究现状更新，首先介绍GSPs和CPPs的理论及重要特征，接着概述它们所实现或改进的广泛应用。我们涵盖了能够制造锥形凹槽结构的技术，特别强调了晶圆级生产方法，并概述了可用于激发和研究GSPs和CPPs的各种基于光子和电子的方法。我们最后讨论了进一步开发等离子体锥形凹槽器件仍面临的挑战，并考虑了这个特定但可能影响深远的主题领域所提供的未来方向。
