Faculty of Physics

Super Slow Motion for Plasmons

Since 2002, an electron microscope that is surface sensitive when applying low-energy electrons has been in operation at the University of Duisburg-Essen. This microscope has been combined with a femtosecond laser system to carry out time-resolved experiments on electron dynamics following the optical excitation of electrons in solid states in a pump-probe experiment. In the DFG priority programme SPP1319 ‘Ultrafast Nanooptics’, this experimental setup was used between 2009 and 2016 to observe the propagation of the density of electron waves on surfaces, known as surface plasmon polaritons, in time and space. A joint publication by authors from the UDE and the University of Kaiserslautern in the ‘Plasmonics’ journal produced a breakthrough in the depiction of plasmon waves on surfaces: by changing the incidence geometry of laser pulses on the surface, the plasmon contrast created in the microscope could be optimised, whereby the simultaneous depiction of plasmons, which propagate in different directions on the surface, was possible for the first time. In the reporting period, this methodology was used on a number of nanooptic problems with plasmons.