Hannover 2010 – scientific programme
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A: Fachverband Atomphysik
A 15: Attosecond Physics I
A 15.3: Talk
Wednesday, March 10, 2010, 17:00–17:15, F 107
High-Order Harmonic Generation at 100 kHz Repetition Rate for Time-Resolved Two-Photon Photoemission — •Christoph Heyl1,2, Jens Güdde1, Anne L’Hullier2, and Ulrich Höfer1 — 1Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, Marburg, Germany — 2Department of Physics, Lund University, Lund, Sweden
Two-photon photoemission (2PPE) has been successfully used to study the electron dynamics of surfaces and interfaces with femtosecond time resolution. With most of the current experimental setups the detectable energies and parallel momenta of electrons are limited by the availability of ultra-short pulsed UV laser systems. Recent progress in generating femtosecond and attosecond VUV pulses by means of high-order harmonic generation (HHG) opens the potential to access the whole Brillouin zone with high time resolution. Time-resolved 2PPE, however, benefits greatly from high repetition rates, whereas harmonics are usually generated at low repetition rates and high intensities.
We present a high-order harmonic source operating with remarkable stability at 100 kHz using a fundamental pulse energy of only 7 µJ. In contrast to earlier perceptions it turns out that high-order harmonics can be efficiently generated even at low pulse energies and thus at high repetition rates [1]. We compare the experimental onditions with theoretical simulations focusing on the characteristics of a tight focus geometry and its consequences for the process of HHG in gases.
[1] F. Lindner et al., Phys. Rev. A. 68, 013814 (2003)