Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 83: Poster Focus Session: Structural Dynamics in Nanoscale Materials, Probed by Ultrafast Electron Pulses
O 83.9: Poster
Mittwoch, 14. März 2018, 18:15–20:30, Poster A
Ultrafast Microscopy of Charge Carrier Motion in Nanoscale Systems — •Faruk Krecinic1, Melanie Müller1, Jannik Malter1, Alexander Paarmann1, Vasily Kravtsov2, Markus Raschke2, and Ralph Ernstorfer1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 2University of Colorado, Boulder, USA
The ultrafast motion of charge carriers at the nanoscale plays a crucial role in our understanding of optoelectronic systems. We recently developed femtosecond point projection microscopy (fs-PPM) as a new technique for visualizing ultrafast charge carrier motion with nanometer resolution [1]. Due to the use of low-energy electrons, the fs-PPM image is highly sensitive to local electric fields. Here we present our recent experiments visualizing the photoionization of silver nanowires excited with intense laser fields. The dynamics of the photoelectrons and the concomitant positive charging of the nanowires is shown to happen on a time scale as short as 40 fs. The field sensitivity of this technique can be further enhanced, down to the level of a single elementary charge, by taking advantage of the phase information of the imaging electron wavepacket, i.e. by performing electron holography. Our recent progress toward the development of femtosecond low-energy electron holography will also be reported. [1] M. Müller et al., Nature Comm. 5, 5292 (2014).