1 Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Straße 61, Dresden 01187, Germany.
2 Faculty of Science and Engineering, Åbo Akademi University Porthansgatan 3, Turku 20500, Finland.
3 Institute of Physics and Astronomy University of Potsdam Karl-Liebknecht-Strasse 24-25, Potsdam 14476, Germany.