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Q: Fachverband Quantenoptik und Photonik

Q 22: Matter Wave Optics II

Q 22.5: Vortrag

Montag, 5. März 2018, 17:15–17:30, K 1.013

Coherence measurements of multiphoton-photoemitted electrons from tungsten nano tips — •Stefan Meier, Takuya Higuchi, Philipp Weber, and Peter Hommelhoff — Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen

Metal nanotips represent widely used coherent electron sources nowadays. By using them as dc field emission tips, an upper limit of their effective source size r_eff of only 0.4 nm was found [1]. This means that they show high spatial coherence properties, enabling matter-wave experiments, such as electron diffraction, holography or electron interferometry, as well as highest resolution electron microscopy. But electron emission from metal nanotips can also be triggered via photoemission. It was shown for tungsten nanotips that r_eff of electrons emitted in a single-photon emission process was almost as small as for dc field-emitted electrons under the same experimental conditions, so the supreme spatial coherence is maintained although the emission process is completely different [2]. By triggering the tips with femtosecond laser pulses it is possible to strongly confine the electron emission in time and therefore add high temporal resolution to these techniques. With the help of electron interference fringes after a CNT-based nanobiprism we here show results on characterizing the spatial coherence properties of electrons emitted via a nonlinear multiphoton photoemission process under illumination with few-cycle laser pulses.

[1] B. Cho et al., Phys. Rev. Lett. 92, 246103 (2004)

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