1. Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Albert-Einstein-Str. 15, 07745 Jena, Germany
2. Max-Planck-Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching, Germany
3. Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching, Germany
4. Celeroton Ltd., Industriestrasse 22, 8604 Volketswil, Switzerland
5. Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, 07745 Jena, Germany
6. Helmholtz-Institute Jena, Fröbelstieg 3, 07743 Jena, Germany