Hannover 2016 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 27: Poster: Quantum Optics and Photonics II

Q 27.41: Poster

Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof

Coherence measurements of electrons from a field-emission tip triggered by few femtosecond laser pulses — •Stefan Meier, Philipp Weber, Takuya Higuchi, and Peter Hommelhoff — Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstrasse 1, 91058 Erlangen

Field-emission tips represent excellent electron sources with regard to spatial coherence properties, which limits the spatial resolution of microscopic and diffraction experiments. Triggering the electron emission from such tips by laser pulses provides additional temporal resolution to these techniques. Recently, with the help of electron interference fringes obtained with a carbon nanotube as an electrostatic biprism, electrons emitted via single-photon absorption of continuous-wave and rather long laser pulses (duration ∼ 21 ps) were shown to exhibit a similarly small effective source radius (0.80 ± 0.05 nm) as that of dc-field emitted electrons (0.55 ± 0.02 nm) [1]. The degree of global coherence of 36% is among the highest ever observed [2]. In this presentation, we will discuss if such supreme spatial coherence is maintained in nonlinear photoemission, triggered by few-cycle near-infrared laser pulses, which is a key to further confine the electron wave packet in time [2]. The current status of the experiment will be reported.

[1] D. Ehberger et al., Phys. Rev. Lett. 114, 227601 (2015).

[2] M. Krüger et al., Nature 475, 78 (2011).