1. Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria.
2. Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria.
3. Joint Quantum Institute, NIST/University of Maryland, College Park, MD 20740, USA.
4. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA.
5. Department of Physics, Technical University of Munich, 85748 Garching, Germany.
6. Munich Center for Quantum Science and Technology, Schellingstr. 4, D-80799 München, Germany.
7. Univ. Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France.