Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 35: Attosecond physics
A 35.2: Hauptvortrag
Donnerstag, 3. März 2016, 15:00–15:30, f107
Multidimensional control of XUV-initiated high harmonic generation — Doron Azoury1, •Michael Krüger1, Henrik R. Larsson2, Sebastian Bauch2, David J. Tannor1, Barry D. Bruner1, and Nirit Dudovich1 — 1Weizmann Institute of Science, Rehovot 76100, Israel — 2University of Kiel, Kiel D-20489, Germany
In XUV-initiated high harmonic generation (HHG), tunneling ionization is replaced by photoionization with an attosecond XUV pulse [1,2]. Ionization and subsequent IR-mediated propagation get decoupled from each other, allowing for a high degree of control and extending high harmonic spectroscopy to inner shells. Here we demonstrate XUV-initiated HHG from helium and neon atoms by combining an attosecond XUV pulse train and an IR pulse and show that the XUV-IR delay controls the timing of ionization. Moreover, by adding a weak second harmonic field and scanning its phase relative to the IR we retrieve even harmonics that oscillate completely out of phase with the odd harmonics [3]. These observations unambiguously reveal the involvement of electron trajectories and the insignificance of tunneling in the process, showing for the first time that ionization and propagation are decoupled and can be controlled independently. A strong-field model and ab-initio calculations corroborate our findings.
[1] K. Schafer et al., PRL 92, 023003 (2004).
[2] G. Gademann et al., NJP 13, 033002 (2011).
[3] O. Pedatzur et al., Nature Physics 11, 815 (2015).