Understanding the ultrafast excitation, detection, transportation, and manipulation of nanoscale spin dynamics in the terahertz (THz) frequency range is critical to developing spintronic THz optoelectronic nanodevices. However, the diffraction limitation of the sub-millimeter waves – THz wavelengths – has impaired experimental investigation of spintronic THz nano-emission. Here, we present an approach to studying laser THz emission nanoscopy from W|CoFeB|Pt metasurfaces with ∼60-nm lateral spatial resolution. When comparing with statistic near-field THz time-domain spectroscopy with and without the heterostructures on fused silica substrates, we find that polarization- and phase-sensitive THz emission nanoscopy is more sensitive than the statistic THz scattering intensity nanoscopy. Our approach opens explorations of nanoscale ultrafast THz spintronic dynamics in optically excited metasurfaces.

中文翻译：

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通过扫描近场纳米显微镜表征自旋电子太赫兹超表面发射

了解太赫兹（THz）频率范围内纳米级自旋动力学的超快激发、检测、传输和操纵对于开发自旋电子太赫兹光电纳米器件至关重要。然而，亚毫米波（太赫兹波长）的衍射限制削弱了自旋电子太赫兹纳米发射的实验研究。在这里，我们提出了一种研究 W|CoFeB|Pt 超表面的激光太赫兹发射纳米显微镜的方法，横向空间分辨率约为 60 nm。当与熔融石英衬底上有或没有异质结构的统计近场太赫兹时域光谱进行比较时，我们发现偏振和相敏太赫兹发射纳米镜比统计太赫兹散射强度纳米镜更敏感。我们的方法开启了光激发超表面中纳米级超快太赫兹自旋电子动力学的探索。