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arXiv 0912.0666cond-mat.mes-hall
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纳米粒子波导中虚局域跃迁的缓冲等离子体激元

Buffering plasmons in nanoparticle waveguides at the virtual-localized transition

Raul A. Bustos-Marun, Eduardo A. Coronado, Horacio M. Pastawski

摘要:

我们研究了从局部激发的纳米粒子(LE-NP)到线性阵列的小纳米粒子的等离子体能量转移,并得到了响应函数的参数依赖性。一个解析表达式使我们能够区分扩展的共振态和本地化的,以及一个难以捉摸的制度的虚拟状态。这最后出现时,共振宽度崩溃,并在它成为一个本地化的状态。与常识相反,当系统具有良好定义的扩展共振态时,最高激发转移不会发生,而是仅发生在虚拟局域跃迁处,其中主等离子体激元模式在通带边缘具有本征频率。在该临界频率下的慢群速度使得激发缓冲成为可能,因此有利于链内的强信号。类似的情况应该出现在许多其他物理系统中。这种转变对波导和LE-NP参数的极端敏感性为等离子体提供了新的工具。

英文摘要:

We study the plasmonic energy transfer from a locally excited nanoparticle (LE-NP) to a linear array of small NPs and we obtain the parametric dependence of the response function. An analytical expression allows us to distinguish the extended resonant states and the localized ones, as well as an elusive regime of virtual states. This last appears when the resonance width collapses and before it becomes a localized state. Contrary to common wisdom, the highest excitation transfer does not occur when the system has a well defined extended resonant state but just at the virtual-localized transition, where the main plasmonic modes have eigenfrequencies at the passband edge. The slow group velocity at this critical frequency enables the excitation buffering and hence favors a strong signal inside the chain. A similar situation should appear in many other physical systems. The extreme sensitivity of this transition to the waveguide and LE-NP parameters provides new tools for plasmonics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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