1. Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Lessingstr. 12 (AWZ), 07743 Jena, Germany
2. Institute of Glass and Ceramics, Department of Materials Science and Engineering, Friedrich Alexander University Erlangen Nuremberg, Martensstr. 5, 91058 Erlangen, Germany
3. Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745 Jena, Germany
4. Institute of Physics, Augsburg University, Universitätsstr. 1, 86159 Augsburg, Germany
5. Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece