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MA: Fachverband Magnetismus

MA 31: Ultrafast Electron and Spin Dynamics

MA 31.6: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-EG

Characterization of an ultrafast MHz electron point source — •Jannik Malter, Melanie Müller, Faruk Krecinic, and Ralph Ernstorfer — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany

Ultrafast electron point sources allow for electron microscopy and diffraction [1] as well as scanning probe techniques [2] with very high spatial and temporal resolution. The laser repetition rate is a crucial parameter as it directly influences statistics of the measurement, and taking the required laser pulse energy into account determines the thermal stress on the tip. We discuss photoemission from a metal tip using an optical parametric amplified laser in the low-MHz regime. Photoemission is either triggered by direct illumination of the apex, or by excitation and nanofocusing of surface plasmon polaritons [3]. Due to the better thermal response of the tip, the latter approach could possibly lead to femtosecond electron holography and contribute to laser-triggered ultrafast STMs.

[1] Müller et al. Femtosecond electrons probing currents and atomic structure in nanomaterials. Nature Comm. 5, 2014

[2] Cocker et al. Tracking the ultrafast motion of a single molecule by femtosecond orbital imaging. Nature 539, 2016

[3] Müller et al. Nanofocused Plasmon-Driven Sub-10 fs Electron Point Source. ACS Photonics 3 (4), 2016