Ultrafast Transmission Electron Microscopy (UTEM) is a powerful technique to study structural and electronic dynamics on the nanoscale.
It serves as an analytical tool with simultaneous femtosecond temporal
and nanometer spatial resolution. Moreover,
UTEM also provides for a unique test bench to study quantum optics phenomena
with free electrons.
This talk will introduce the implementation of UTEM with nanoscale field
emitter sources, which offer ultrashort electron pulses of exceptional beam
quality and spatial coherence. Examples of structural and magnetization
dynamics probed by UTEM will be discussed. Moreover, the mechanisms involved in
free-electron beams interacting with optical fields near nanostructures and
surfaces will be described, emphasizing quantum effects. The coherent
manipulation of the longitudinal and transverse degrees of freedom of
free-electron wave functions is shown, and the preparation and characterization
of attosecond electron pulse trains will be demonstrated.
 A. Feist et al., “Ultrafast transmission electron
microscopy using a laser-driven field emitter: Femtosecond resolution with a
high coherence electron beam”, Ultramicroscopy 176, 63 (2017).
 A. Feist et al., “Nanoscale diffractive probing
of strain dynamics in ultrafast transmission electron microscopy”, Struct. Dyn.
5, 014302 (2018).
 A. Feist, K. E.
Echternkamp, J. Schauss, S. V. Yalunin, S. Schäfer, and C. Ropers,
“Quantum coherent optical phase modulation in an ultrafast transmission
electron microscope”, Nature 521,
 K. E. Echternkamp, A.
Feist, S. Schäfer, and C. Ropers, “Ramsey-type phase control of free electron
beams”, Nature Phys. 12, 1000
 K. E. Priebe, C.
Rathje, S. V. Yalunin, T. Hohage, A. Feist, S. Schäfer, and C. Ropers, “Attosecond
Electron Pulse Trains and Quantum State Reconstruction in Ultrafast
Transmission Electron Microscopy”, Nat. Phot. 11, 793