Janus magneto-electric nanosphere dimers exhibiting unidirectional visible light scattering and strong electromagnetic field enhancement.
Janus magneto-electric nanosphere dimers exhibiting unidirectional visible light scattering and strong electromagnetic field enhancement.
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DOI：
10.1021/nn505606x
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发表时间：
2015-01
期刊：
影响因子：
17.1
通讯作者：
Hao Wang;Pu Liu;Y. Ke;Yunkun Su;Lei Zhang;N. Xu;S. Deng;Huanjun Chen
中科院分区：
文献类型：
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作者：
Hao Wang;Pu Liu;Y. Ke;Yunkun Su;Lei Zhang;N. Xu;S. Deng;Huanjun Chen
在纳米尺度下将入射光引导到特定方向对于未来的信号传输和检测的纳米光子学应用非常重要。实现这一目的的先决条件是开发具有高效单向光散射特性的纳米结构。本文从理论和实验两个方面，构思并演示了由金和硅纳米球组成的异质结Janus二聚体的单向可见光散射行为。通过仔细调整两个纳米球的大小和间距，Janus二聚体可以支持具有光谱重叠和可比强度的电和磁偶极子模式。这两种模式的干涉导致了窄带单向散射行为，前向散射增强，后向散射抑制。通过将二聚体排列成一维链结构可以进一步改善方向性。此外，二聚体还显示出显著的电磁场增强。这些结果不仅对发光器件、太阳能电池、滤光器和各种表面增强光谱学的应用很重要，而且对我们进一步理解纳米尺度下的光-物质相互作用也很重要。
Steering incident light into specific directions at the nanoscale is very important for future nanophotonics applications of signal transmission and detection. A prerequisite for such a purpose is the development of nanostructures with high-efficiency unidirectional light scattering properties. Here, from both theoretical and experimental sides, we conceived and demonstrated the unidirectional visible light scattering behaviors of a heterostructure, Janus dimer composed of gold and silicon nanospheres. By carefully adjusting the sizes and spacings of the two nanospheres, the Janus dimer can support both electric and magnetic dipole modes with spectral overlaps and comparable strengths. The interference of these two modes gives rise to the narrow-band unidirectional scattering behaviors with enhanced forward scattering and suppressed backward scattering. The directionality can further be improved by arranging the dimers into one-dimensional chain structures. In addition, the dimers also show remarkable electromagnetic field enhancements. These results will be important not only for applications of light emitting devices, solar cells, optical filters, and various surface enhanced spectroscopies but also for furthering our understanding on the light-matter interactions at the nanoscale.