1. Institute for Solid State Physics Friedrich‐Schiller‐University Jena 07743 Jena Germany
2. Department of Electrical and Computer Engineering University of Wisconsin – Madison Madison WI 53706 USA
3. Department of Materials Science and Engineering University of Wisconsin – Madison Madison WI 53706 USA
4. Leibniz Institute of Photonic Technology 07745 Jena Germany
5. Innovavent GmbH 37077 Göttingen Germany
6. Department of Physics University of Wisconsin – Madison Madison WI 53706 USA