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O: Fachverband Oberflächenphysik

O 5: Ultrafast Electron Dynamics at Surfaces and Interfaces I

O 5.8: Vortrag

Montag, 18. März 2024, 12:15–12:30, MA 041

Development and characterization of an ultrafast scanning electron microscope — •Paul H. Bittorf¹ and Nahid Talebi^1,2 — ¹Institute for Experimental and Applied Physics, Kiel University, Leibnizstraße 19, D-24118 Kiel, Germany — ²Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Christian-Albrechts-Platz 4, D-24118 Kiel, Germany

A variety of processes are involved within the interaction of free-electron wave packets with light or matter, such as coherent and incoherent excitation of the investigated material. Understanding these interaction processes of pulsed electron beams with shaped light fields or nanostructured matter is crucial to achieve a favored shaping of electron wave packets, as well as exploring the dynamics of material excitations. Therefore, we developed an ultrafast scanning electron microscope (USEM) for exploring the dynamics at the nanoscale and at the femtosecond time regime. Our setup is based on the combination of a commercial SEM with an ultrafast laser system, where a laser-driven pulsed electron source is achieved via the photoemission process. In addition to the electron beam excitation, a time-delayed laser pulse is focused onto the sample to induce an optical near-field and implement a time-resolved pump-probe measurement. The interaction properties of electrons with matter are analyzed through the emitted light, either cathodoluminescence (CL) or photoluminescence. Here, we report on the technical aspects of the development and characterization of our USEM setup and present measurements of the photoemitted pulsed electron beams and a novel fiber-based CL detector.

Keywords: ultrafast scanning electron microscope; pulsed electron beam; cathodoluminescence spectroscopy; pump-probe measurement; electron-light-matter interaction