Near-Field Plasmonics of an Individual Dielectric Nanoparticle above a Metallic Substrate
Near-Field Plasmonics of an Individual Dielectric Nanoparticle above a Metallic Substrate
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DOI：
10.1021/jp400963f
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发表时间：
2013-04-18
影响因子：
3.7
通讯作者：
Mahajan, Sumeet
中科院分区：
文献类型：
--
作者：
Hutter, Tanya;Huang, Fu Min;Mahajan, Sumeet
我们模拟并讨论了介电纳米粒子放置在非常靠近金属基板的系统中的局部电场增强。本文采用有限元数值模拟的方法来理解这种介质NP-on-mirror系统的场增强机理。在适当的激励条件下，颗粒与衬底之间的间隙成为一个“热点”，即一个强电磁场区域。我们还展示了放置在金属衬底上的介质NP的光学性质如何影响纳米间隙中的等离子体场增强，并表征了间隙中的约束。我们的研究有助于理解和设计金属衬底上的介电NPs系统，这种系统可以像传统的全等离子体结构一样有效地处理SERS，荧光和非线性现象。
We simulate and discuss the local electric-field enhancement in a system of a dielectric nanoparticle placed very near to a metallic substrate. We use finite-element numerical simulations in order to understand the field-enhancement mechanism in this dielectric NP-on-mirror system. Under appropriate excitation conditions, the gap between the particle and the substrate becomes a "hot spot", i.e., a region of intense electromagnetic field. We also show how the optical properties of the dielectric NP placed on a metallic substrate affect the plasmonic field enhancement in the nanogap and characterize the confinement in the gap. Our study helps to understand and design systems with dielectric NPs on metallic substrates which can be equally as effective for SERS, fluorescence, and nonlinear phenomena as conventional all plasmonic structures.