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Q: Fachverband Quantenoptik und Photonik
Q 39: Ultrashort Laser Pulses
Q 39.6: Vortrag
Mittwoch, 13. März 2019, 15:30–15:45, S SR 211 Maschb.
Strong-field control of photoemission from tungsten needle tips with a two-color laser field — •Timo Paschen1, Philip Dienstbier1, Lennart Seiffert2, Thomas Fennel2, and Peter Hommelhoff1 — 1Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen — 2Institut für Physik, Universität Rostock, 18051 Rostock
Ionization by two-color laser fields with well-defined relative phase allows one to tune and control electronic dynamics on the (sub-) femtosecond time scale. Recently, we demonstrated that in the perturbative photoemission regime electron emission induced by a fundamental pulse can be modulated with a contrast of up to 97.5% when superimposing a weak second harmonic. This modulation is based on the interference between two different quantum channels involved in the photoelectron emission process [1,2]. In the strong-field photoemission regime, a model based on the time-dependent Schrödinger Equation and also the three-step model predict a two-color phase-dependent modulation of the plateau and high-energy cutoff in electron energy spectra [3]. In this talk we show similar field-driven dynamics in two-color photoemission from needle tips by employing a highly nonlinear fiber that generates IR laser pulses with sub-two cycle duration.
[1] M. Förster et al., Phys. Rev. Lett. 117, 217601 (2016).
[2] T. Paschen et al., J. Mod. Opt. 64, 10-11, 1054-1060 (2017).
[3] L. Seiffert et al., J. Phys. B. 51, 134001 (2018).