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SYCF: Symposium Cluster und Fullerene
SYCF 3: Metallcluster: Dynamik
SYCF 3.4: Vortrag
Dienstag, 16. März 1999, 14:45–15:00, MP1
Femtosecond optical second harmonic generation by metal nanoparticles: novel method for the determination of surface plasmon dephasing time — •F. Tr"ager1, M. Simon1, and T. Vartanyan2 — 1Fachbereich Physik, Universit"at Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, E-mail: Traeger@Physik.Uni-Kassel.de — 2State Optical Institute, P. O. Box 953, St. Petersburg, 197101, Russia, E-mail tigran@jamnet.spb.su
Measurements of surface plasmon dephasing times are of great importance since they provide the possibility to distinguish between different damping mechanisms of collective electronic excitations in metal clusters. Unfortunately, however, the decay time cannot be extracted from the line width of linear optical spectra since they usually exhibit inhomogeneous broadening of unknown size. Therefore, pump-and-probe experiments by optical second harmonic generation (SHG) have recently been performed.
It was commonly believed that autocorrelation traces provide direct access to the plasmon dephasing times if performed with interferometric accuracy and femtosecond time resolution. In this contribution we do not only present a theory which accounts for the inhomogeneous broadening and shows that inhomogeneous broadening also plays a role in SHG autocorrelation studies. We also describe how the homogeneous and the inhomogeneous broadening can be determined separately provided linear spectroscopy data and results of time domain SHG autocorrelation measurements for the same sample are available.