Mainz 2017 – scientific programme

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A: Fachverband Atomphysik

A 29: Ultrashort Laser Pulses: Generation and Applications (with Q)

A 29.8: Talk

Thursday, March 9, 2017, 16:15–16:30, P 5

Temporal characterization of femtosecond electron bunches in a laser-triggered scanning electron microscope — •Norbert Schönenberger, Martin Kozák, Joshua McNeur, and Peter Hommelhoff — Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen

To study the dynamics in atomic and condensed matter systems, including phonon excitations and electron dynamics in atoms and molecules, sub-femtosecond timescales need to be resolved. The temporal resolution of these ultrafast experiments with electron beams is limited by both the electron dispersion in vacuum and the Coulomb repulsion between electrons. Here we present the temporal characterization of electron bunches emitted from a Schottky-type tip source inside a standard scanning electron microscope (SEM). Photoemission from the tip is induced by 100 fs ultraviolet pulses. The temporal profile of the bunch is obtained by energy- and time-resolved cross-correlation measurements between the electron bunch and the electromagnetic near-field mode of an infrared laser pulse traversing a periodic dielectric nanostructure. We study the influence of the bunch charge and the settings of the electron column on the longitudinal behaviour of the electron packets emitted from the tip to gain further insight into the behaviour of new electron sources, sub-femtosecond-resolved dielectric laser accelerator (DLA) diagnostics and electron diffraction and microscopy experiments [1].

[1] Martin Kozák, et al. Optical gating and streaking of free-electrons with attosecond precision, arXiv:1512.04394 (2015)