Karl Franzens University Graz
Graz University of Technology
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Karl Franzens University Graz | Graz University of Technology | |
2 Photon Photoemission and Time-Resolved Microscopy The excitation and propagation of light in metallic nanostructures by means of plasmons is one of the most promising approaches to overcome the diffraction limit and arrive at sub-wavelength nano-optics. This perspective has created a tremendous interest in the interaction of light with metallic particles. We use the self organization of Ag islands and wires on (vicinal) Si(100) to form structures that act as resonators for localized surface plasmons and that form guides for surface plasmon polariton waves. To detect the plasmonic excitation, a spectroscopic photoemission microscopope (SPE-PEEM) was combined with a femtosecond Ti:Sapphire laser oscillator as an illumination source. This two photon photoemission microscopy is particularly well suited for studying plasmons in small structures, because the resolution of the microscopes is sufficiently high, the parallel detection allows videorate imaging even during structure formation, and the plasmon resonances enhance the nonlinear photoemission yield and provide for the direct visualization of the plasmon in the nanostructure. Furthermore, the time-structure of the illumination allows observation of the propagation of the initial excitation on a femtosecond timescale in a pump-probe experiment. |