Chemical interface damping of surface plasmon excitation in metal nanoparticles:a study by persistent spectral hole burning

C. Hendrich, J. Bosbach, F. Stietz, F. Hubenthal, T. Vartanyan, F. Träger

Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology - CINSaT, Universität Kassel

Received: 17 March 2003/Revised version: 8 April 2003
Published online: 16 July 2003

Abstract
As demonstrated recently, persistent spectral hole burning in the optical spectra of metal nanoparticles makes possible the determination of the ultrafast dephasing time T2 of surface plasmon excitation. Here, the influence of the chemical environment on the dephasing process is investigated under ultrahigh vacuum conditions by depositing an adsorbate on the nanoparticles. By comparing the optical spectra and the widths of the generated holes of the nanoparticles with and without adsorbate coverage, the influence of chemical interface damping on the dephasing process is examined. The potential of the novel procedure is demonstrated for silver nanoparticles on sapphire and quartz substrates using SO2 as the adsorbate. A drastic decrease of T2 for the adsorbate-covered nanoparticles is observed and explained by dynamic charge transfer of electrons from the particles into and out of adsorbate states of the SO2 molecules.

PACS 78.67.Bf; 61.46.+w; 71.45.Gm; 73.22.Lp; 68.43.-h, © Springer-Verlag 2003