1. Faculty of Physics, University of Vienna, Boltzmanngasse 5,
A-1090 Vienna, Austria and German Aerospace Center (DLR), Institute of Quantum Technologies, Söflinger Straße 100, 89077 Ulm,
Germany
2. Faculty of Physics, University of Vienna, Boltzmanngasse 5,
A-1090 Vienna, Austria
3. Tel Aviv University, The Center for Nanosciences and Nanotechnology, Tel Aviv 69978, Israel and
School of Chemistry, The Raymond and Beverly Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel