Dresden 2011 – scientific programme

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A: Fachverband Atomphysik

A 18: Interaction with strong or short laser pulses I

A 18.2: Talk

Wednesday, March 16, 2011, 16:45–17:00, BAR 106

High-Harmonic Generation via Continuum-Wave Packet Interference — •Markus C. Kohler, Christian Ott, Philipp Raith, Robert Heck, Ines Schlegel, Christoph H. Keitel, and Thomas Pfeifer — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

High-Harmonic Generation is investigated theoretically in the over-the-barrier ionization regime revealing a significant coherent radiation response of continuum-continuum (CC) harmonics. Their emission happens when two parts of the electronic wave function being ionized in different half cycles of the laser recollide at the same time. The emission energy of these CC harmonics is exactly the kinetic-energy difference of the two wave packets.

A time-frequency analysis shows that the process entirely dominates coherent HHG emission after the ground state has been depleted. Moreover, we show that CC harmonics exhibit a different phase-matching behavior compared to the traditional continuum-bound harmonics and can therefore be isolated. Our analytic results suggest that CC harmonics might be employed for a new type of molecular tomography where the potential-energy landscape of a molecule could be imaged. Additionally, we advance the interference model of HHG.
[1] Markus C. Kohler, Christian Ott, Philipp Raith, Robert Heck, Iris Schlegel, Christoph H. Keitel, and Thomas Pfeifer, Phys. Rev. Lett 105, 203902 (2010)