Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research, University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.
Analyst. 2018 Dec 17;144(1):13-30. doi: 10.1039/c8an01667d.
The structural characteristics of plasmonic nanostructures directly influence their plasmonic properties, and therefore, their potential role in applications ranging from sensing and catalysis to light- and energy-harvesting. For a structure to be compatible with a selected application, it is critical to accurately tune the plasmonic properties over a specific spectral range. Fabricating structures that meet these stringent requirements remains a significant challenge as plasmon resonances are generally narrow with respect to the considered selected spectral range. Adapted from their well-established role in GHz applications, plasmonic fractal structures have emerged as architectures of interest due to their ability to support multiple tunable resonances over broad spectral domains. Here, we review the advancements that have been made in the growing field of fractal plasmonics. Iterative and space-filling geometries that can be prepared by advanced nanofabrication techniques, notably electron-beam lithography, are presented along with the optical properties of such structures and metasurfaces. The distributions of electromagnetic enhancement for some of these fractals is shown, along with how the resonances can be mapped experimentally. This review also explores how fractal structures can be used for applications in solar cell and plasmon-based sensing applications. Finally, the future areas of physical and analytical science that could benefit from fractal plasmonics are discussed.
等离子体纳米结构的结构特征直接影响其等离子体特性，因此，它们在从传感和催化到光和能量收集等应用中的潜在作用。为了使结构与选定的应用兼容，关键是要在特定的光谱范围内准确地调整等离子体特性。制造满足这些严格要求的结构仍然是一个重大挑战，因为等离子体共振相对于所选的光谱范围通常很窄。受其在 GHz 应用中成熟角色的启发，等离子体分形结构因其能够在宽光谱域中支持多个可调谐共振而成为人们关注的结构。在这里，我们回顾了分形等离子体学这一日益发展的领域所取得的进展。我们介绍了可以通过先进的纳米制造技术（特别是电子束光刻）制备的迭代和空间填充几何形状，以及这些结构和超表面的光学特性。展示了这些分形中的一些分形的电磁增强分布，以及如何通过实验映射共振。本文还探讨了分形结构如何应用于太阳能电池和基于等离子体的传感应用。最后，讨论了分形等离子体学可能受益的未来物理和分析科学领域。
