arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2104.01997physics.optics
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用电子束揭示双曲声子极化激元的纳米尺度限制效应

Revealing Nanoscale Confinement Effects on Hyperbolic Phonon Polaritons with an Electron Beam

Andrea Konečná, Jiahan Li, James H. Edgar, F. Javier García de Abajo, Jordan A. Hachtel

摘要:

六方氮化硼(hBN)中的双曲声子极化激元(HPhPs)使得能够在纳米尺度下直接操纵中红外线,这比自由空间光波长低许多数量级。高分辨率单色电子能量损失光谱(EELS)有助于测量能量延伸到中红外的激发,同时保持纳米级的空间分辨率,使其成为检测HPhPs的理想选择。电子束是一个精确的源和探针的HPhPs,这使我们能够进行新的实验,以观察纳米级的限制在HPhP结构和直接提取hBN极化激元分散体的两种模式在大部分的薄片和模式沿边缘。我们的测量揭示了技术上重要的非平凡现象,如由环境异质性引起的局部极化激元,由于二维干涉增强和抑制激发,以及边缘边界上的纳米级异质性对边缘限制极化激元的高动量激发的强烈修改。我们的工作为基于双曲型极化激元的中红外光学器件的设计开辟了令人兴奋的前景。

英文摘要:

Hyperbolic phonon polaritons (HPhPs) in hexagonal boron nitride (hBN) enable the direct manipulation of mid-infrared light at nanometer scales, many orders of magnitude below the free-space light wavelength. High resolution monochromated electron energy-loss spectroscopy (EELS) facilitates measurement of excitations with energies extending into the mid-infrared while maintaining nanoscale spatial resolution, making it ideal for detecting HPhPs. The electron beam is a precise source and probe of HPhPs, that allows us to perform novel experiments to observe nanoscale confinement in HPhP structures and directly extract hBN polariton dispersions for both modes in the bulk of the flake and modes along the edge. Our measurements reveal technologically important non-trivial phenomena, such as localized polaritons induced by environmental heterogeneity, enhanced and suppressed excitation due to two-dimensional interference, and strong modification of high-momenta excitations of edge-confined polaritons by nanoscale heterogeneity on edge boundaries. Our work opens exciting prospects for the design of real-world optical mid-infrared devices based on hyperbolic polaritons.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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