Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 14: Plasmonics and Nanooptics II: Light-Matter Interaction and Spectroscopy

O 14.3: Topical Talk

Monday, March 18, 2024, 15:30–16:00, MA 042

Time-resolved interaction of the electron system with strong surface plasmon polariton fields — •Frank Meyer zu Heringdorf — Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg, Germany

Time-resolved experiments often rely on femtosecond laser pulses to create a non-equilibrium situation in the electron system of a surface. The specifics of the created nonequilibrium hereby depends on the detailed spatiotemporal properties of the excitation field. It has been demonstrated that by controlling surface plasmon polaritons (SPPs) it is possible to create unique (even topologically non-trivial) polarization fields at surfaces. Experimental knowledge of the SPP vector field on a few hundred nm length- and a fs time-scale can be obtained using vector microscopy and polarimetry, where time-resolved, probe-polarization-dependent two photon photoemission data is obtained in a spectroscopic low energy electron microscope (SPE-LEEM). Using Archimedean spirals for excitation, strong SPP foci can be created that exhibit highly-nonlinear electron emission, and the ponderomotive interaction of the electron with the SPP field during the photoemission process can be used to quantify the field strength. Time- and angle-resolved experiments at a SPP focus clarify the intermediate states involved in the emission process and demonstrate that SPPs can coherently couple to electronic states in above-threshold electron emission.

Keywords: Photoemission Microscopy; Surface Plasmon Polaritons; time-resolved phenomena