Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 8: Poster I
A 8.27: Poster
Dienstag, 9. März 2010, 16:30–19:00, Lichthof
Analysis of the recombination step in high-order harmonic generation — •Elmar Vincent van der Zwan1,2, Maria Tudorovskaya1,2, and Manfred Lein1 — 1Centre for Quantum Engineering and Space-Time Research (QUEST) and Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany — 2Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 31432 Kassel, Germany
Although single-active-electron harmonic spectra can be calculated routinely, both using the time-dependent Schrödinger equation and trajectory-based approaches, they still contain many unexplored aspects that have implications for molecular imaging. We study the question to what extent the recombination step in high-order harmonic generation is described by the laser-field-free continuum-bound transition amplitude. For different alignment angles of the molecule we study the harmonics generated from H2+ by linearly polarized laser pulses of both physical and artificial types. This is compared to harmonics from field-free collisions with Gaussian electron wave packets. We thus disentangle the influence of the Coulombic potential and the laser field on the two-center interference. The results provide information on the recombining electronic wave packet that can be used in imaging techniques, such as molecular orbital tomography. We find significant ellipticity in the polarization of the harmonics. Furthermore, we study the role of resonance states in harmonic generation, aiming at verifying the common belief that the time scales in high-order harmonic generation are too short for sharp resonances to develop fully.