High brightness ultrafast Transmission Electron Microscope based on a laser-driven cold-field emission source: principle and applications

TL;DR

This paper introduces an ultrafast Transmission Electron Microscope utilizing a laser-driven cold-field emission source, detailing its design, simulation predictions, pulse broadening effects, and potential applications in ultrafast holography and diffraction.

Contribution

It presents a novel ultrafast TEM setup based on laser-driven emission, with detailed simulations and experimental characterizations of electron pulse properties and broadening effects.

Findings

Predicted femtosecond electron pulse properties via simulations

Characterized spectral and temporal broadening effects

Demonstrated potential for ultrafast holography and diffraction

Abstract

We report on the development of an ultrafast Transmission Electron Microscope based on a laser-driven cold-field emission source. We first describe the instrument before reporting on numerical simulations of the laser-driven electron emission. These simulations predict the temporal and spectral properties of the femtosecond electron pulses generated in our ultrafast electron source. We then discuss the effects that contribute to the spatial, temporal and spectral broadening of these electron pulses during their propagation from the electron source to the sample and finally to the detectors of the electron microscope. The spectro-temporal properties are then characterized in an electron/photon cross-correlation experiment based on the detection of electron energy gains. We finally illustrate the potential of this instrument for ultrafast electron holography and ultrafast electron diffraction.