From Isolated Metaatoms to Photonic Metamaterials: Evolution of the Plasmonic Near-Field
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- 作者：Felix von Cube ; Stephan Irsen ; Richard Diehl ; Jens Niegemann ; Kurt Busch ; Stefan Linden
- 刊名：Nano Letters
- 出版年：2013
- 出版时间：February 13, 2013
- 年：2013
- 卷：13
- 期：2
- 页码：703-708
- 全文大小：457K
- 年卷期：v.13,no.2(February 13, 2013)
- ISSN：1530-6992
文摘
Metamaterials are artificial media which can provide optical properties not available from natural materials. These properties often result from the resonant excitation of plasmonic modes in the metallic building blocks (鈥渕etaatoms鈥? of the metamaterial. Electromagnetic interactions between the metaatoms significantly modify the resonances of the individual metaatoms and influence the optical properties of the whole metamaterial. To better understand these interactions, we study in this Letter the evolution of the plasmonic near-field in the course of the transition from an isolated metaatom, in our case a split-ring resonator (SRR), to a photonic metamaterial via electron energy-loss spectroscopy. For small SRR ensembles, we observe the formation of discrete optical bright and dark modes due to coupling of the metaatoms. Large SRR arrays reveal a quasi-continuum of modes in the interior and distinct edge modes at the boundaries of the array. Our experimental results are in excellent agreement with numerical calculations.<br>