Koutenský Petr, Streshkova Neli Laštovičková, Moriová Kamila, Chirita Mihaila Marius Constantin, Knápek Alexandr, Burda Daniel, Kozák Martin
Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, Prague CZ-12116, Czech Republic.
Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, Brno CZ-61200, Czech Republic.
ACS Photonics. 2025 Jul 21;12(8):4452-4459. doi: 10.1021/acsphotonics.5c00864. eCollection 2025 Aug 20.
Ultrafast electron microscopy aims for imaging transient phenomena occurring on nanoscale. One of its goals is to visualize localized optical and plasmonic modes generated by coherent excitation in the vicinity of various types of nanostructures. Such imaging capability was enabled by photon-induced near-field optical microscopy, which is based on spectral filtering of electrons inelastically scattered due to the stimulated interaction with the near-field. Here, we report on the development of ultrafast four-dimensional (4D) scanning transmission electron microscopy, which allows us to image the transverse components of the optical near-field while avoiding the need of electron spectral filtering. We demonstrate that this method is capable of imaging the integrated Lorentz force generated by optical near-fields of a tungsten nanotip and the ponderomotive potential of an optical standing wave with a spatial resolution of 21 nm.
超快电子显微镜旨在对纳米尺度上发生的瞬态现象进行成像。其目标之一是可视化由各种类型纳米结构附近的相干激发产生的局域光学和等离子体模式。光子诱导近场光学显微镜实现了这种成像能力，它基于对因与近场的受激相互作用而非弹性散射的电子进行光谱滤波。在此，我们报告了超快四维（4D）扫描透射电子显微镜的发展情况，该显微镜使我们能够对光学近场的横向分量进行成像，同时无需电子光谱滤波。我们证明，这种方法能够以21纳米的空间分辨率对钨纳米尖端的光学近场产生的综合洛伦兹力以及光学驻波的有质动力势进行成像。
