Quantitative insights into non-uniform plasmonic hotspots due to symmetry breaking induced by oblique incidence
Quantitative insights into non-uniform plasmonic hotspots due to symmetry breaking induced by oblique incidence
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对倾斜入射引起的对称性破缺导致的不均匀等离子体热点的定量见解
DOI：
10.1039/d0cp03470c
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发表时间：
2020
影响因子：
3.3
通讯作者：
Xuemin Yang
中科院分区：
文献类型：
--
作者：
Yong Zhou;Hongliang Li;Guanhua Zhang;Dong Wei;Lan Zhang;Yujie Meng;Xianfeng Zheng;Zhibo Ma;Jie Zeng;Xuemin Yang
局域表面等离子体激元共振引起了人们的广泛关注，主要是由于它增强了近场电场，等离子热点通过斜入射的光的对称性破缺的预测影响的等离子热点的强度。然而，相关的实验研究，定量比较与理论还很缺乏。在这里，我们可视化的偏振依赖的等离子热点的三角形银纳米片通过双入射光电子发射显微镜（PEEM），揭示了非均匀的近场增强。在斜入射下，在偏振平均PEEM图像中识别出两个亮点和一个暗点，不同于正常照明，其中预期具有相等强度的亮点。在偏振相关的PEEM图像中，等离子热点出现在三角形Ag纳米片的特定角落，并以与偏振角旋转一致的方式旋转。模拟结果在定量水平上较好地再现了光电子的实验强度图。这项工作提供了一个定量的理解，入射光相对于等离子体天线的方向如何影响近场增强。
Localized surface plasmon resonance draws great attentions mainly due to its enhanced near electric field, i.e., plasmonic hotspots. The symmetry breaking via oblique incidence of light is predicted to influence the intensity of plasmonic hotspots. However, relevant experimental investigation in quantitative comparison with theory is still lacking. Here, we visualize the polarization-dependent plasmonic hotspots of a triangular Ag nanoplate through oblique-incidence photoemission electron microscopy (PEEM), revealing a non-uniform near-field enhancement. Under oblique incidence, two bright spots and one dark spot were identified in the polarization-averaged PEEM image, different from that for normal illumination where bright spots with equal intensity are anticipated. In polarization-dependent PEEM images, plasmonic hotspots appeared at specific corners of a triangular Ag nanoplate, and rotated in a manner consistent with the rotation of polarization angle. The experimental intensity maps of the photoelectron were well reproduced by simulation on a quantitative level. This work provides a quantitative understanding of how the orientation of incidence light relative to a plasmonic antenna influences the near-field enhancement.