Strong Nanoscale Optical Activity Localized in Two-Dimensional Chiral Metal Nanostructures
Strong Nanoscale Optical Activity Localized in Two-Dimensional Chiral Metal Nanostructures
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DOI：
10.1021/jp409072h
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发表时间：
2013-11-14
影响因子：
3.7
通讯作者：
Okamoto, Hiromi
中科院分区：
文献类型：
--
作者：
Narushima, Tetsuya;Okamoto, Hiromi
具有手性形状的纳米结构表现出类似手性分子的行为，并显示出光学活性。手性纳米结构的光学活性应该近似地由整个纳米结构上的局部光学活性的总和给出。在这项工作中，我们报告了100 nm尺度的空间分辨圆二色性（CD），并与宏观上获得的S形金纳米结构的CD光谱的结果进行比较。具有两个旋向的局部CD信号在单个纳米结构中共存，并且CD的空间分布反映了纳米结构的手性对称性。当在整个纳米结构上积分时，局部CD信号约为局部CD信号最大值的1%，这与宏观CD信号大致一致。这表明，即使仅观察到微小的CD信号作为纳米结构样品的宏观光学活性，也可能存在显著的纳米尺度局部CD信号。
Nanostructures with chiral shapes behave like chiral molecules and show optical activity. The optical activity of the chiral nanostructure should be given approximately by the summation of the local optical activities over the entire nanostructure. In this work, we report 100-nm-scale spatially resolved circular dichroism (CD) and compare the results with the macroscopically obtained CD spectrum of S-shaped gold nanostructures. Local CD signals with both directions of handedness coexisted in the individual nanostructures, and the spatial distribution of the CD reflected the chiral symmetry of the nanostructure. When integrated over the entire nanostructure, the local CD signal was approximately 1% of the maximum of the local CD signal, which approximately coincided with the macroscopic CD signal. This indicates that prominent nanoscale local CD signals might exist even if only a tiny CD signal is observed as the macroscopic optical activity of the nanostructured sample.