Confined Optical Fields in Nanovoid Chain Structures Directly Visualized by Near-Field Optical Imaging
Confined Optical Fields in Nanovoid Chain Structures Directly Visualized by Near-Field Optical Imaging
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DOI：
10.1021/jp108781q
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发表时间：
2011-02-10
影响因子：
3.7
通讯作者：
Okamoto, Hiromi
中科院分区：
文献类型：
--
作者：
Kim, Su Il;Imura, Kohei;Okamoto, Hiromi
在玻璃衬底上制备了线性排列的Au薄膜上的纳米空泡链结构。使用孔径型近场扫描光学显微镜的双光子激发成像技术显示了由于个别结构的局域光场分布。在每个空穴间隙处观察到由空穴链引起的受限光场，激发偏振平行于空穴链轴线。二聚体空穴的电磁场模拟与实验结果定性地吻合。在垂直于链轴的激发偏振下，只观察到微弱的光场。进一步详细讨论了这些系统中局域光场的特性，包括与光学中的巴比内原理有关的特性。我们的研究可能会在分子传感和光化学方面开辟新的可能性。
Linearly aligned nanovoid chain structures on Au thin films were fabricated on glass substrates. Two-photon excitation imaging techniques using an aperture-type near-field scanning optical microscope revealed localized optical field distributions due to the individual structures. Confined optical fields due to the void chains were observed at each interstitial gap between voids with excitation polarization parallel to the chain axis. Electromagnetic field simulations of dimeric voids qualitatively matched the experimental results. Under excitation polarization perpendicular to the chain axis, only weak optical fields were observed. Further detailed characteristics of localized optical fields in these systems, including those in relation to Babinet's principle in optics, were discussed. Our study may open up new possibilities in molecular sensing and photochemistry.