Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

A: Fachverband Atomphysik

A 10: Poster: Interaction with strong or short laser pulses

A 10.5: Poster

Montag, 23. März 2015, 17:00–19:00, C/Foyer

Spin polarization of electrons in a strong laser field — Alexander Hartung, •Alina Laucke, Maksim Kunitski, and Reinhard Dörner — Institut für Kernphysik, Goethe-Universität Frankfurt am Main

Atoms exposed to a strong laser field (intensities in the range of 10¹⁴ W/cm² and higher at 800 nm) are efficiently ionized. I. Barth and O. Smirnova predicted that electrons which are created by strong-field-tunnelionization from rare gas atoms are spin polarized [1]. They propose two effects to be responsible for the spin selectivity: first, they argue that the probability for tunnelionization by circular light depends on the sign of the magnetic quantum number m of the electron [2]. Second, there are different strong-field-tunnelionization probabilities for different electron spins because the spin-orbit-interaction makes electrons with spin parallel to m more weakly bound than those with spin antiparallel to m.

We have performed a first experiment on Xenon, ionized by a circularly polarized 800 nm laser pulse at peak intensities of 4.4 and 6.6·10¹⁴ W/cm² [3]. We used a Spin Mott detector in order to measure the spin polarization of the photo-electrons. The preliminary results strongly indicate the existence of this theoretically predicted spin-polarization. The experimentally measured strength of the effect as well as the electron energy and intensity dependences are in good agreement with the theory. [1] I. Barth, O. Smirnova; Phys. Rev. A 88, 013401 (2013) [2] I. Barth, O. Smirnova; Phys. Rev. A 84, 063415 (2011) [3] A. Hartung; Master Thesis, University Frankfurt (2014)