Dresden 2009 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
O: Fachverband Oberflächenphysik
O 20: Nano-optics of metallic and semiconducting nanostructures (time resolved)
O 20.3: Talk
Tuesday, March 24, 2009, 11:00–11:15, SCH A216
Ultrafast dephasing of the surface plasmon polaritons in metallic nanoparticles: Influence of the chemical environment — •Martin Wortmann, Nils Borg, Frank Hubenthal, and Frank Träger — Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology – CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132 Kassel
It is well known that intrinsic size effects for metal nanoparticles have a significant influence on the electron dynamics and lead to a reduction of the dephasing time of the surface plasmon resonance. To take this effect into account, the parameter A has been introduced, which quantifies the influence of all independent damping contributions Ai, with A = ∑Ai (Matthiessen law). Although theoretically well understood, an exact knowledge of A as well as a microscopic understanding of the involved processes, in particular of the chemical surrounding, are still lacking.
In this contribution we present first results on the influence of an inhomogeneous chemical environment on the A-parameter. We have investigated silver nanoparticles supported on sapphire and quartz substrates. The obtained A-parameters amount to Asap = 0,20 nm/fs and to Aqua = 0,54 nm/fs, respectively. The latter value is higher, because quartz induces chemical damping. A subsequent coverage of the samples with SO2 opens a second damping channel and the A-parameters increase. Interestingly, for both SO2 covered samples the A-parameter is the same and amounts to A = 1,76 nm/fs. This leads to the conclusion, that the two different damping channels are not independent.