1. Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague 12116, Czech Republic
2. Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague 12116, Czech Republic
3. MIND-IN UB, Department of Electronic and Biomedical Engineering, Universitat de Barcelona, Martí i Franquès 1, 08030 Barcelona, Spain
4. Research School of Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
5. IMTEK, Faculty of Engineering, Albert-Ludwigs-University Freiburg, Georges-Köhler-Alle 103, 79110 Freiburg, Germany