Darmstadt 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
K: Fachverband Kurzzeitphysik
K 5: Attosekunden Experimente
K 5.1: Vortrag
Dienstag, 11. März 2008, 15:30–15:45, 2D
Attosecond Ionization Gating of High-Harmonic Generation — •Thomas Pfeifer1,2, Aurélie Jullien1,2, Mark J. Abel1,2, Phillip M. Nagel1,2, Daniel M. Neumark1,2, and Stephen R. Leone1,2 — 1Departments of Chemistry and Physics, University of California, Berkeley, CA 94720, USA — 2Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
When an intense (∼1014-1015 W/cm2) laser pulse interacts with an atomic system, ionization occurs and high-order harmonics are produced. We present experimental evidence that the ultrafast ionization at a quickly-rising leading edge of a laser pulse can be used to turn off the harmonic production process on a sub-optical-cycle timescale. The last, most intense cycle to produce harmonics before the turn-off then produces the highest photon energies, therefore leading to an isolated attosecond pulse after high-pass filtering. Instead of requiring a cosine-pulse for isolated attosecond pulse generation as in the conventional scheme, the carrier-envelope phase now becomes a free parameter to tune the center photon energy of the attosecond pulse. The same method also allows the production of isolated attosecond pulses with multi-cycle driver pulses. We also describe an interferometric way of extracting the multiplicity of attosecond pulses (number of pulses in the pulse train) in different parts of the high-harmonic spectrum.
Ref.: T. Pfeifer et al., Opt. Express, accepted (2007).