Quantitative Insights into a Plasmonic Ruler Equation from the Perspective of Enhanced Near Field
Quantitative Insights into a Plasmonic Ruler Equation from the Perspective of Enhanced Near Field
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从增强近场的角度定量洞察等离激元标尺方程
DOI：
10.1021/acs.jpca.2c07702
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发表时间：
2022-12-26
影响因子：
2.9
通讯作者：
Huang，Wanxia
中科院分区：
文献类型：
--
作者：
Zhou，Yong;Zhu，Jiahui;Huang，Wanxia
近场耦合引起的共振波长的等离子激元漂移使人们能够光学地测量纳米级的距离。在经验上，提出了等离子体激元位移与粒子间距之间的关联方程。虽然它已被广泛应用于分析模拟和实验结果，但对于等离子体激元标尺方程的特征指数形式和其中的普遍衰变常数的潜在物理机制却知之甚少。在这项工作中，我们试图从等离子体激元近场增强的角度来解密这些问题。基于等离子体激元位移的准简正模解析公式，证明了指数衰减电场是导致等离子体激元标尺方程呈指数形式的关键原因，并定量地发现等离子体激元标尺方程中的普适衰减常数实际上反映了增强近场的范围。这项工作有望加深对相应等离子体过程中光-物质相互作用机制的理解。
The plasmonic shift of resonance wavelength induced by near-field coupling enables one to measure nanoscale distances optically. Empirically, the well-known ruler equation correlating plasmon shift with interparticle spacing was proposed. Though it has been widely used in analyzing simulation and experimental outcomes, little is known about the underlying physical mechanism of the characteristic exponential form of the plasmon ruler equation and the universal decay constant therein. In this work, we attempt to decrypt these from the perspective of plasmon near-field enhancement. Based on an analytical quasi-normal mode formula for plasmon shifts, we proved that the exponential decaying electric field is the critical reason that results in the exponential form of the plasmon ruler equation and quantitatively, we found that the universal decay constant in the plasmon ruler equation actually reflects the range of the enhanced near field. This work hopefully helps to deepen the understanding of the mechanism of light–matter interaction in corresponding plasmonic processes.