Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 92: Poster Session - Ultrafast Electron Dynamics at Surface and Interfaces II

O 92.6: Poster

Wednesday, March 18, 2020, 18:15–20:00, P2/1OG

Localized linear photoemission from a cold field emitter — •Alexander Schröder, Jelto Jordan, Nora Bach, Christopher Rathje, and Sascha Schäfer — Institute of Physics, University of Oldenburg, Germany

Ultrafast transmission electron microscopy (UTEM) combines the femtosecond temporal resolution of a pump-probe approach with the nanometer spatial resolution of a TEM. Further improving the spatio-temporal resolution in UTEM requires the development of novel high-coherence photoelectron sources with stable laser-driven emission currents over long time periods.

Here, we report on the current status of our development of a laser-driven cold field emitter. Using a field ion microscope, we prepared atomically clean (311)-oriented sharp tungsten tips. Above a certain threshold potential localized photoemission from these tips is observed using a continuous-wave 355-nm laser beam focused onto the tip apex. Photocurrent characterization yields a stable, linear photoemission regime in the fA-range, ideally suited for application in UTEM.