Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 50: Time-resolved spectroscopy II

O 50.3: Vortrag

Freitag, 31. März 2006, 11:45–12:00, WIL C207

Local Plasmon Excitations in Silver Nanodots: Spatio-temporal evolution and coupling dynamics probed by interferometric time-resolved PEEM — •Jörg Lange, Carsten Wiemann, Daniela Bayer, Oksana Gaier, Martin Rohmer, Christian Schneider, Michael Bauer, and Martin Aeschlimann — University of Kaiserslautern, Department of Physics, Kaiserslautern, Germany

We have studied the temporal and spatial evolution of collective electronic excitations (Mie-plasmons) in silver nanostructures using phase resolved interferometric two-photon photoemission electron microscopy (PR-2PPEEM). The interference of a reference He:Ne laser beam was used to achieve a temporal resolution in the attosecond regime of the piezo driven scanning interferometer, which we used for the two-photon photoemission pump-probe experiment. At the same time, the 2PPE-yield collected by the photoemission electron microscope allows a lateral resolution better than 40 nm. We demonstrate that this setup enables to monitor the temporal response of collective electronic excitations (Mie-plasmons) to an excited femtosecond laser pulse in silver nanodots. Regarding the plasmon induced inhomogeneous spatial distribution of the 2PPE-yield from single nanodots we observe a complex dependence on the temporal phase between the pump and the probe pulse. Furthermore, we were able to resolve spatio-temporal variations in the 2PPE-signal from pairs of close-lying nanodots, thus enabling insight into the dynamics of coupled plasmon excitations.