Ultrafast Nanooptics PD Dr. Walter Pfeiffer Physikalisches Institut der Universitaet Wuerzburg Collective electron dynamics at interfaces are of fundamental importance for many different aspects in surface science, like surface chemistry, catalysis and electronic properties of nanostructured surfaces. The presentation covers time-resolved experiments using supported Ag nanoparticles illustrating the role of collective excitations in two-photon-photoemission. In a second part more general aspects of the excitation of plasmons with ultrashort polarization shaped laser pulses is discussed. The optical near field in the vicinitiy of arbitrarily shaped nanoscale objects is utilized to control the spatial and temporal evolution of the electric field. This control mechanism opens new routes to time-resolved spectroscopy on the nanoscale.