1. Institute of Solid State Physics Friedrich Schiller University Jena 07743 Jena Germany
2. Institute of Applied Physics Abbe Center of Photonics Friedrich Schiller University Jena 07745 Jena Germany
3. Institute of Theoretical Solid State Physics Karlsruhe Institute of Technology 76131 Karlsruhe Germany
4. Karlsruhe School of Optics and Photonics Karlsruhe Institute of Technology 76131 Karlsruhe Germany
5. Faculty of Physics Lomonosov Moscow State University Moscow 119991 Russia
6. Institute of Nanotechnology Karlsruhe Institute of Technology 76021 Karlsruhe Germany
7. Max Planck School of Photonics Albert‐Einstein‐Str. 7 07745 Jena Germany