Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 78: Nanostructures at Surfaces IV: Various Aspects
O 78.3: Talk
Thursday, March 10, 2016, 11:00–11:15, S052
Circular dichroism and spin polarization from artificial nanostructures — •Daniel Nürenberg1, Andrew Mark2, Matthias Kettner1, Peer Fischer2, and Helmut Zacharias1 — 1Westfälische Wilhelms-Universität, Münster — 2Max Plank Institut für intelligente Systeme, Stuttgart
Metal nanohelices are receiving growing interest because of their giant plasmon-enhanced optical circular dichroism. We address circular dichroism in multi-photon photoemission from metal nanohelix arrays triggered by polarized ultra-short laser pulses from an optical parametric chirped-pulse amplifier. We use time-of-flight spectroscopy and Mott polarimetry to measure the energy distribution and spin polarization of the emitted electrons. Helices made of non-magnetic Ag:Ti and Ag:Cu alloys on a silicon wafer emit photoelectrons with a polarization dependence in yield and longitudinal spin polarization. The results are compared with single-photon photoemission measurements.