Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 37: Plasmonics and Nanooptics V: Light-Matter Interaction

O 37.6: Talk

Tuesday, March 21, 2017, 15:15–15:30, TRE Ma

Tracking Plasmon Propagation by Terahertz-Streaking at Metal Nanotips — •Lara Wimmer, Benjamin Schröder, Murat Sivis, Georg Herink, and Claus Ropers — IV. Physical Institute - Solids and Nanostructures, University of Göttingen, Germany

We resolve the propagation time of surface plasmon polaritons (SPP) traveling along the shaft of gold nanotips [1] employing Terahertz (THz) near-field streaking spectroscopy [2, 3]. Surface plasmon polaritons are launched by femtosecond near-infrared (NIR) pulses in a grating coupler at the shaft of the nanostructure, 50 *m from the tip end. At the apex, the nanofocused SPPs induce the (multiphoton) emission of photoelectrons [1], which are streaked in the locally enhanced near-field of a THz transient incident on the tip. Reference spectrograms are obtained by direct NIR-excitation of the apex. The observed temporal shift between both streaking spectrograms provides a direct measure of the group delay [4] in SPP propagation from the grating to the tip apex.

[1] Schröder et al., Phys. Rev. B 92, 085411 (2015).

[2] Wimmer et al., Nature Physics 10, 432-436 (2014).

[3] Herink et al., New Journal of Physics 16, 123005 (2014).

[4] Kravtsov et al., Opt. Lett. 38, 1322-1324 (2013)