Coupled-Dipole Modeling and Experimental Characterization of Geometry-Dependent Trochoidal Dichroism in Nanorod Trimers
Coupled-Dipole Modeling and Experimental Characterization of Geometry-Dependent Trochoidal Dichroism in Nanorod Trimers
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DOI：
10.1021/acsphotonics.1c00073
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发表时间：
2021-03-17
期刊：
影响因子：
7
通讯作者：
Landes, Christy F.
中科院分区：
文献类型：
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作者：
Baiyasi, Rashad;Goldwyn, Harrison J.;Landes, Christy F.
贵金属纳米颗粒具有表面等离子体共振，将电磁波限制在光的衍射极限以下，使其成为近场光学天线的有效构建块。通过对纳米天线光学性质的更好的理解，有效的预测和设计纳米天线系统是很容易的。在这里，我们利用一个直观的扇形金纳米棒三聚体的耦合偶极模型，结合实验来研究近场和远场效应对光学二色性的影响，使用线性和摆线极化，侧翻场的运动与三聚体的几何形状相匹配。我们的耦合偶极子模型预测了我们在实验中观察到的线性和摆线二向色性，并且我们证明了摆线强度调制可以通过改变金纳米棒三聚体的几何参数来调节和逆转。简单的分析模型，加上易于理解的可视化，为预测性纳米天线设计应用提供了一个有用的框架。
Noble metal nanoparticles host surface plasmon resonances that confine electromagnetic waves below the diffraction limit of light, making them effective building blocks for near-field optical antennas. Efficient prediction and design of nanoantenna systems are facilitated by improved understanding of their optical properties. Here, we utilize an intuitive coupled-dipole model for fan-shaped gold nanorod trimers together with experiments to investigate the role of near- and far-field effects upon optical dichroism using both linear and trochoidal polarizations with cartwheeling field motion matching the geometry of the trimers. Our coupled-dipole model predicts the linear and trochoidal dichroism that we observe in experiments, and we demonstrate that trochoidal intensity modulation can be tuned and reversed by varying the geometric parameters of the gold nanorod trimers. Simple analytical models, coupled with easily understood visualizations, provide a useful framework for predictive nanoantenna design applications.