Institut für Physik - Humboldt-Universität zu Berlin and Max-Born-Institut
Publications>>Electron energy loss spectroscopy on freestanding perforated gold films
Electron energy loss spectroscopy on freestanding perforated gold films
M. Prämassing, T. Kiel, S. Irsen, K. Busch, and S. Linden (2021)
Physical Review B 103:115403
Summary (expand/hide)
We report on a combined far- and near-field study of surface plasmon polaritons on freestanding perforated gold films. The samples were fabricated by focused ion beam milling of a periodic hole array into a carbon membrane followed by thermal evaporation of gold and plasma ashing of the carbon film. Optical transmission spectra showed a series of characteristic features, which can be attributed to the excitation of surface plasmon modes via the periodic nanohole array. The corresponding near-field distributions were mapped by electron energy loss spectroscopy. In addition to the optically bright surface plasmon modes, we observed in the near-field a dark plasmon mode which is absent in the normal incidence far-field spectra. Our experimental results are in good agreement with numerical computations based on a discontinuous Galerkin time-domain method.