Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source

TL;DR

This paper presents a novel ultrafast Transmission Electron Microscope that uses a laser-driven cold field emission source, achieving the highest brightness reported and enabling advanced imaging, diffraction, spectroscopy, and holography with ultrashort electron pulses.

Contribution

The development of an ultrafast TEM with a laser-triggered cold field emission source that attains record brightness and supports multiple advanced electron microscopy techniques.

Findings

Achieved the highest brightness reported for UTEMs.

Demonstrated imaging, diffraction, and spectroscopy with ultrashort electron pulses.

Performed electron holography using ultrashort electron pulses.

Abstract

We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined. The measured brightness is the largest reported so far for UTEMs. Examples of imaging, diffraction and spectroscopy using ultrashort electron pulses are given. Finally, the potential of this instrument is illustrated by performing electron holography in the off-axis configuration using ultrashort electron pulses.