Visualizing the optical field structures in metal nanostructures
Visualizing the optical field structures in metal nanostructures
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DOI：
10.1021/jz401023d
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发表时间：
2013-06
影响因子：
5.7
通讯作者：
H. Okamoto;K. Imura
中科院分区：
文献类型：
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作者：
H. Okamoto;K. Imura
贵金属纳米结构由于等离子体共振而产生纳米尺度的受限光场，并且它们在光谱分析、光化学反应、光学器件、生物成像等方面具有潜在的新颖应用。为了设计用于特定应用的纳米级受限光场，需要对光场进行可视化以提供必要的信息。本研究采用近场光学显微镜观察光场。金属纳米结构中的光场的直接可视化的例子，提出了与基于近场成像的独特的光谱特性的分析。对于金纳米棒等单个纳米颗粒，根据颗粒形状和尺寸，可以看到颗粒附近的等离子体驻波函数和/或增强的局部场。在组装的纳米粒子中，粒子之间的差距位置处的增强光场被可视化，从而阐明了组装的机理。
Noble metal nanostructures yield confined optical fields on a nanometer scale due to plasmon resonances, and they have potentially novel applications in spectroscopic analysis, photochemical reactions, optical devices, bioimaging, and so forth. To design nanoscale confined optical fields for use in specific applications, visualization of the fields is needed to provide essential information. We adopted near-field optical microscopy to visualize the optical fields in the present study. Examples of the direct visualization of optical fields in metal nanostructures are presented together with the analysis of the unique spectroscopic characteristics based on near-field imaging. For single nanoparticles such as gold nanorods, the plasmon standing wave functions and/or enhanced local fields near the particles were visualized depending on the particle shapes and sizes. In the assembled nanoparticles, the enhanced optical fields at the gap sites between the particles were visualized, thus elucidating the mechanis...