Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 18: Attosecond physics I

A 18.5: Vortrag

Dienstag, 13. März 2012, 15:30–15:45, V47.03

Attosecond control of electrons emitted from a nanoscale metal tip — •Michael Krüger, Markus Schenk, Michael Förster, Sebastian Thomas, Lothar Maisenbacher, and Peter Hommelhoff — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching bei München, Germany

By focusing low-power few-cycle Ti:sa pulses tightly onto sharp tungsten tips it is possible to reach a strong-field photoemission regime, a prerequisite for performing attosecond science. We have recently observed strong-field effects such as peak suppression and peak shifting [1] and rescattering [2] in this system. Here we use carrier-envelope phase (CEP) stabilized pulses and measure photoelectron spectra for varying CEP. We observe a CEP dependent current modulation that increases in amplitude to about 100% for high-energy electrons. Furthermore, we observe a clear change in the peak visibility of the high-energy plateau part of the spectrum when the phase is changed by π. The presence (absence) of spectral interference indicates that high-energy electrons are emitted within two time windows (one window) of sub-optical-cycle duration. Quantum mechanical theory models confirm this notion and show that photoelectrons from the metal tip can be steered with attosecond precision by changing the CEP, in analogy to atomic gases. We discuss results deepening the understanding of the processes involved.

[1] M. Schenk, M. Krüger, P. Hommelhoff, PRL 105, 257601 (2010)

[2] see contribution of M. Schenk et al. at this conference

[3] M. Krüger, M. Schenk, P. Hommelhoff, Nature 475, 79 (2011)