Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Plasmonics and Nanooptics III: Light-Matter Interaction
O 21.1: Vortrag
Montag, 20. März 2017, 17:00–17:15, TRE Ma
Momentum distribution of hot electrons in resonantly excited gold nanorods revealed by time of flight k-resolving photoemission spectromicroscopy — •Martin Lehr1, Benjamin Foerster2,3, Katja Krüger2, Mathias Schmitt2, Carsten Sönnichsen2, Gerd Schönhense1, and Hans Joachim Elmers1 — 1Institut für Physik, Johannes Gutenberg-Universität, Staudinger Weg 7, D-55128 Mainz, Germany — 2Institut für physikalische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, D-55128 Mainz, Germany — 3Graduate School for Excellence Materials Science in Mainz, Johannes Gutenberg University Mainz, Staudingerweg 9, D-55128 Mainz, Germany
We investigate plasmon assisted photoemission from individual Au nanorods using a time-of-flight momentum resolving photoemission electron microscope (ToF k-PEEM). The Au nanorods are taylored to obtain a localized plasmon polartion resonance wavelength of 800 nm with a linewidth of just 44 nm. The Au nanorods adhere to a transparent In-Sn oxide substrate enabling illumination from the rear side at normal incidence. The two momentum components parallel to the surface and the kinetic energy of the electrons are measured simultaneously. Both properties depend on laser power and polarization confirming a plasmon assisted emission process mediated by the optical field enhancement at the nanorod's ends. The exponential intensity decrease of emitted electrons with increasing kinetic energy reveals the distribution of hot electrons leading to an additional emission process with a characteristic homogeneous momentum distribution.