Centre d’Élaboration de Matériaux et d’Etudes Structurales (UPR 8011)


Accueil > Recherche > NeO : Nano-Optique et Nanomatériaux pour l’Optique > Dynamique ultrarapide dans les systèmes nanométriques

Ultrafast Transmission Electron Microscopy

The FemTOTEM project aims at developing an Ultrafast Transmission Electron Microscope (UTEM) based on a high brightness laser-driven field emission electron source. This will be achieved by bringing together a femtosecond laser source and a customized cold-field emission Transmission Electron Microscope (CFEG-TEM). This combination of femtosecond time resolution, high brightness (allowing high spatial resolution and coherence of electrons) and energy resolution will have a unique potential for frontier research in nanophysics and materials science.

The first part of this project involves instrumental developments. First, we will demonstrate and characterize laser driven field emission from the customized electron source of a commercial 200kV TEM. The femtosecond cold field emission gun that we have already mounted in a dedicated Ultra High Vacuum (UHV) bench will be completely characterized in terms of emitted current and energy spectrum as a function of laser parameters and extraction voltage. Then, it will be transferred on a TEM column. Its potential for electron microscopy experiments will be thoroughly investigated first on routine TEM applications and later on more demanding experiments. A new attachment allowing light injection and collection on the TEM sample, already designed, will enable us to perform original experiments involving electrons and photons. The principle of an ultrafast TEM is show on the Figure. An ultrashort laser pulse excites the sample inside the objective lens. A second, delayed, laser pulse triggers the emission of ultrashort electron pulses inside the electron microscope.

Ultrafast Transmission Electron Microscope

This project involves two research groups of CEMES (I3EM and NeO) and is a collaboration between CEMES and LPS-Orsay (Mathieu Kociak).

 

 

Financial Support :

The FemtoTEM project is supported by Institut de Physique of CNRS and Agence Nationale de la Recherche  (grant ANR-14-CE26-0013).

 

Contact :

Arnaud ARBOUET  (arbouet chez cemes.fr) & Florent HOUDELLIER (florent chez cemes.fr)