Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 21: Interaction with Strong or Short Laser Pulses I
A 21.7: Vortrag
Donnerstag, 11. März 2010, 15:45–16:00, F 107
The Rescattering Effect in Strong-Field Photodetachment of Negative Ions. — •Boris Bergues1,2, Hannes Hultgren1, Igor Kiyan1, Azra Gazibegović-Busuladžić3, Dejan Milošević3,4, and Wilhelm Becker4 — 1Albert-Ludwigs-Universität, Freiburg, Germany. — 2Max-Planck-Institut für Quantenoptik, Garching, Germany. — 3University of Sarajevo, Sarajevo, Bosnia and Herzegovina. — 4Max-Born-Institut, Berlin, Germany.
We present experimental and theoretical results on photodetachment of negative ions in strong laser fields. Since in a negative ion the outer electron is bound to the atomic core by a short-range potential, such a system is best suited to verify predictions of Keldysh-Faisal-Reiss (KFR)-like theories. In our previous studies on F− using linearly as well as circularly polarized light, we showed that the KFR theory for direct electrons quantitatively describes all the features of the measured potodetachment spectra. In the present work we expose Br− to strong infrared laser pulses of linear polarization. The angle-resolved spectrum of photoelectrons is recorded using an electron imaging technique. The observed photoelectron spectra exhibit a high-energy plateau along the laser polarization direction, which is not described by the KFR-theory for direct electrons. In contrast, predictions of the rescattering theory are in very good agreement with the measured data. This fact enables us to assign the origin of the observed plateau to the rescattering effect. Our findings represent the first observation of electron rescattering in above-threshold photodetachment of an atomic system with a short-range potential.