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arXiv 1007.4428physics.optics
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界面附近金纳米颗粒的衍射阵列:基底的关键作用

Diffractive arrays of gold nanoparticles near an interface: critical role of the substrate

Baptiste Auguié, Xesús M. Bendaña, William L. Barnes, F. Javier García de Abajo

摘要:

等离子体纳米天线的周期性阵列的光学性质受到阵列平面中的相干多重散射的强烈影响,当波长与周期相称时,这导致透射和反射中的尖锐光谱共振。我们证明了底物的存在(即,非对称折射率环境)可以抑制粒子之间的长程耦合并抑制晶格共振,这与最近的实验结果一致。我们发现衬底到覆盖层的折射率对比度和阵列与界面之间的距离是决定衍射耦合强度的关键参数。我们严格的电磁模拟很好地再现了一个简单的分析模型。这些发现在周期性结构的设计和评估其光学谐振在传感和其他光子技术中的潜在用途中是重要的。

英文摘要:

The optical properties of periodic arrays of plasmonic nanoantennas are strongly affected by coherent multiple scattering in the plane of the array, which leads to sharp spectral resonances in both transmission and reflection when the wavelength is commensurate with the period. We demonstrate that the presence of a substrate (i.e., an asymmetric refractive-index environment) can inhibit long-range coupling between the particles and suppress lattice resonances, in agreement with recent experimental results. We find the substrate-to-superstrate index contrast and the distance between the array and the interface to be critical parameters determining the strength of diffractive coupling. Our rigorous electromagnetic simulations are well reproduced by a simple analytical model. These findings are important in the design of periodic structures and in the assessment of their optical resonances for potential use in sensing and other photonic technologies.

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