1. Otto Schott Institute of Materials Research Friedrich‐Schiller‐Universität Jena Fraunhoferstr. 6 Jena 07743 Germany
2. Institute of Applied Physics Abbe Center of Photonics Friedrich‐Schiller‐Universität Jena Albert‐Einstein‐Str. 15 Jena 07745 Germany
3. Fraunhofer Institute for Applied Optics and Precision Engineering Albert‐Einstein‐Str. 7 Jena 07745 Germany