1. Institute for Quantum Optics, Ulm University, Ulm 89081, Germany
2. Center for Integrated Quantum Science and Technology (IQST), Ulm University, Albert-Einstein-Allee 11, Ulm 89081, Germany
3. Institute of Physics and Center for Nanotechnology, University of Münster, Münster D-48149, Germany
4. Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, Heidelberg 69120, Germany
5. GREMAN, UMR 7347 CNRS, INSA-CVL, Tours University, Tours 37200, France
6. SoN─Center for Soft Nanoscience, Münster 48149, Germany