Light–matter interactions are commonly probed by optical spectroscopy, which, however, has some fundamental limitations such as diffraction-limited spatial resolution, tiny momentum transfer, and noncontinuous excitation/detection. In this work, through the use of scanning transmission electron microscopy–electron energy loss spectroscopy (STEM-EELS) with ultrawide energy and momentum match and subnanometer spatial resolution, the longitudinal Fabry–Perot (FP) resonating modes and the transverse whispering-gallery modes (WGMs) in individual SiC nanowires are simultaneously excited and detected, which span from near-infrared (∼1.2 μm) to ultraviolet (∼0.2 μm) spectral regime, and the momentum transfer can range up to 10⁸ cm^–1. The size effects on the resonant spectra of nanowires are also revealed. This work provides an alternative technique to optical resonating spectroscopy and light–matter interactions in dielectric nanostructures, which is promising for modulating free electrons via photonic structures.

中文翻译：

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电子显微镜探测具有超宽能量和动量匹配的 SiC 纳米线中的电子-光子相互作用

光与物质的相互作用通常通过光谱学进行探测，然而，光谱学具有一些基本的限制，例如衍射限制的空间分辨率、微小的动量传递和非连续激发/检测。在这项工作中，通过使用具有超宽能量和动量匹配以及亚纳米空间分辨率的扫描透射电子显微镜-电子能量损失光谱 (STEM-EELS)，纵向法布里-珀罗 (FP) 共振模式和横向回音壁模式单个 SiC 纳米线中的 (WGM) 被同时激发和检测，其光谱范围从近红外 (~1.2 μm) 到紫外 (~0.2 μm) 光谱范围，动量传递范围可达 10 ⁸ cm ^-1. 还揭示了尺寸对纳米线共振光谱的影响。这项工作为介电纳米结构中的光学共振光谱和光-物质相互作用提供了一种替代技术，有望通过光子结构调制自由电子。