Lund Laser Centre

Lund University

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Time-resolved photoemission electron microscopy of nanostructures

Time-resolved photoemission microscopy (TR-PEEM) combines the high time-resolution of optical pump-probe techniques with the few-nm spatial resolution of photoelectron emission microscopy. This makes TR-PEEM suitable for investigating ultrafast dynamics on the nanoscale. In our TR-PEEM setup, we employ a commercial PEEM (30 nm spatial resolution) in combination with a tunable femtosecond laser source delivering 10-20 fs pulses in the range from 470 nm to 950 nm. We carry out investigations of ultrafast charge carrier dynamics within single nanostructures on their natural time scale. In the experiments, we use the PEEM to image the spatial photoelectron distribution as a function of pump-probe delay time. In addition, the PEEM is equipped with an electron energy filter; this makes it possible to carry out time and spatially resolved photoelectron spectroscopy measurements. Our ongoing research focuses on ultrafast dynamics of photoexcited charge carriers in semiconductor nanostructures and their correlation with local structure and composition. In the future, we plan to integrate an optical pulse shaper for the generation of complex laser pulse sequences into the setup. This will open up the possibility of performing coherent multidimensional spectroscopy on the nanoscale (2D Nanoscopy).