Real-Space Mapping of the Strongly Coupled Plasmons of Nanoparticle Dimers

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• 作者：Deok-Soo Kim ; Jinhwa Heo ; Sung-Hyun Ahn ; Sang Woo Han ; Wan Soo Yun ; Zee Hwan Kim
• 刊名：Nano Letters
• 出版年：2009
• 出版时间：October 14, 2009
• 年：2009
• 卷：9
• 期：10
• 页码：3619-3625
• 全文大小：349K
• 年卷期：v.9,no.10(October 14, 2009)
• ISSN：1530-6992

文摘

We carried out the near-field optical imaging of isolated and dimerized gold nanocubes to directly investigate the strong coupling between two adjacent nanoparticles. The high-resolution (10 nm) local field maps (intensities and phases) of self-assembled nanocube dimers reveal antisymmetric plasmon modes that are starkly different from a simple superposition of two monomeric dipole plasmons, which is fully reproduced by the electrodynamics simulations. The result decisively proves that, for the closely spaced pair of nanoparticles (interparticle distance/particle size 0.04), the strong Coulombic attraction between the charges at the interparticle gap dominates over the intraparticle charge oscillations, resulting in a hybridized dimer plasmon mode that is qualitatively different from those expected from a simple dipole−dipole coupling model.