Quantitative and Direct Near-Field Analysis of Plasmonic-Induced Transparency and the Observation of a Plasmonic Breathing Mode

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• 作者：Worawut Khunsin ; Jens Dorfmüller ; Moritz Esslinger ; Ralf Vogelgesang ; Carsten Rockstuhl ; Christoph Etrich ; Klaus Kern
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：February 23, 2016
• 年：2016
• 卷：10
• 期：2
• 页码：2214-2224
• 全文大小：675K
• ISSN：1936-086X

文摘

We investigated experimentally and numerically in the optical near-field a plasmonic model system similar to a dolmen-type structure for phenomena such as plasmon-induced transparency. Through engineering of coupling strength, structure orientation, and incident angle and phase of the excitation source it was possible to control near-field excitation of the dark modes. We showed that quantitative analysis of near-field amplitude and excitation strength provided essential information that allowed identifying the interaction between the bright and the dark mode and how it causes the formation of plasmon-induced transparency features and a Fano resonance. In addition, we introduced a mechanism to excite field distributions in plasmonic structures that cannot be accessed directly using far-field illumination and demonstrated the excitation of a dark mode akin to a symmetry-forbidden plasmonic breathing mode using a linearly polarized far-field source.