Structural dynamics probed by high-coherence electron pulses

TL;DR

This paper reviews recent advances in ultrafast electron imaging, highlighting improvements in beam coherence that enable detailed studies of structural dynamics at the nanoscale using techniques like ULEED and UTEM.

Contribution

It introduces developments in coherent ultrafast electron sources and their application to surface and nanoscale structural dynamics imaging.

Findings

First application of Ultrafast Low-Energy Electron Diffraction (ULEED)

Enhanced coherence in pulsed electron beams for imaging

Potential of Ultrafast Transmission Electron Microscopy (UTEM) for future research

Abstract

Ultrafast measurement technology provides essential contributions to our microscopic understanding of the properties and functions of solids and nanostructures. Atomic-scale vistas with ever-growing spatial and temporal resolution are offered by methods based on short pulses of x-rays and electrons. Time-resolved electron diffraction and microscopy are among the most powerful approaches to investigate non-equilibrium structural dynamics in excited matter. In this article, we discuss recent advances in ultrafast electron imaging enabled by significant improvements in the coherence of pulsed electron beams. Specifically, we review the development and first application of Ultrafast Low-Energy Electron Diffraction (ULEED) for the study of structural dynamics at surfaces, and discuss novel opportunities of Ultrafast Transmission Electron Microscopy (UTEM) facilitated by laser-triggered field emission sources. These and further developments will render coherent electron beams an essential component in the future of ultrafast nanoscale imaging.