Characterization of Nonradiative Bloch Modes in a Plasmonic Triangular Lattice by Electron Energy-Loss Spectroscopy
Characterization of Nonradiative Bloch Modes in a Plasmonic Triangular Lattice by Electron Energy-Loss Spectroscopy
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DOI：
10.1021/acsphotonics.8b00936
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发表时间：
2018-10
期刊：
影响因子：
7
通讯作者：
Daichi Yoshimoto;H. Saito;S. Hata;Y. Fujiyoshi;H. Kurata
中科院分区：
文献类型：
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作者：
Daichi Yoshimoto;H. Saito;S. Hata;Y. Fujiyoshi;H. Kurata
近年来，电子束光谱学在纳米光子和等离子体系统的模式分析中引起了极大的关注。理论上，电子能量损失谱(EELS)提供了各种电磁模式和非辐射模式的电磁局域态密度信息。然而，与电磁Bloch模的EELS分析相关的例子并不多。在这里，我们进行了EELS测量，以表征具有三角形晶格的等离子体晶体中面向第一带隙的非辐射带边模式，该晶体以形成完整的带隙而闻名。与基于群论的解析模型和基于时域有限差分方法的数值模拟相比，得到的光谱图像清楚地确定了上、下带边模式的特征。EELS谱还揭示了上、下带边等离子体声子态密度的差异，这为我们提供了更多的信息。
Electron beam spectroscopy has recently attracted much attention in the modal analysis of nanophotonic and plasmonic systems. In principle, electron energy-loss spectroscopy (EELS) provides information about the electromagnetic local density of states of all sorts of electromagnetic modes as well as nonradiative modes. However, there have not been many examples related to the EELS analyses for electromagnetic Bloch modes. Herein, EELS measurements are performed for the characterization of nonradiative band-edge modes facing the first bandgap in a plasmonic crystal with a triangular lattice, which is well-known for its full bandgap formation. The obtained spectrum images clearly determine the characteristics of the lower and upper band-edge modes, compared with an analytical model based on group theory and a numerical simulation by the finite-difference time-domain method. The EELS spectra also reveal differences in the plasmonic density of states between the lower and upper band-edges, which provides info...