Hannover 2020 – scientific programme

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SYAD: Symposium SAMOP Dissertation Prize 2020

SYAD 1: SAMOP Dissertation Prize

SYAD 1.1: Invited Talk

Tuesday, March 10, 2020, 11:00–11:30, e415

Electron Pulse Control with Terahertz Fields — •Dominik Ehberger — Ludwig-Maximilians-Universität München — Max-Planck-Institut für Quantenoptik, Garching

Ultrashort pulses of free electrons enable the visualization of ultrafast processes in complex specimen on the atomic level via time-resolved diffraction and microscopy techniques. However, the temporal resolution of these techniques has been limited by the duration of the probing electron pulses, suffering from Coulomb repulsion and dispersion.

In my talk, I will show how all-optical methods for manipulating electron beams promise to overcome these limitations. Using laser-generated, single-cycle terahertz transients, we compress electron pulses from a duration of hundreds of femtoseconds to below 30 fs and detect them with few-femtosecond accuracy by means of terahertz-based streaking. This method further allows us to retrieve electron spectra with few-eV resolution and potentially beyond. Also, we can tilt electron pulses along their propagation axis in a controlled fashion. Data from this experiment indicates a fundamental link between angular dispersion and tilt angle of an electron pulse, which is well known for optical pulses, but now observed for matter waves, too. Terahertz pulses or, more generally, the cycles of light are therefore instrumental to control and shape ultrafast electron pulses to almost any desire.

With these advancements, time-resolved imaging with electrons approaches a new regime, namely that of ultrafast dynamics on sub-nanometer and sub-femtosecond length and time scales, the primary dimensions of fundamental light-matter interaction.