Electron Imaging in Action: Attosecond Electron Diffraction and Microscopy

Abstract

In the last two decades, the generation of attosecond extreme ultraviolet pulses and the advancement of attosecond spectroscopic techniques allowed for real-time observation of electron motion in matter. However, attosecond spectroscopy provides insufficient information about the electron motion trajectory in real space. Therefore, ultrafast electron microscopy (UEM) and diffraction (UED) imaging tools were developed to image the ultrafast dynamics in the four dimensions of time and space. These UEM and UED tools have found various imaging applications in physics, chemistry, and biology. However, existing technical challenges limit the temporal resolution of UEM and UED to the few-hundred femtosecond regime. Therefore, all prior imaging studies recorded only the motion of atoms on the timescale of picoseconds to several-hundred femtoseconds. In this chapter, we present the development and the applications of UEM and UED in imaging the ultrafast dynamics of matter. Moreover, we explain approaches to achieve the attosecond temporal resolution in these imaging tools to establish the attosecond electron diffraction and attomicroscopy fields to image electron motion in time and real space.