1. Light Technology Institute Karlsruhe Institute of Technology 76131 Karlsruhe Germany
2. Institute of Microstructure Technology Karlsruhe Institute of Technology 76344 Eggenstein-Leopoldshafen Germany
3. Institute of Photonics and Quantum Electronics Karlsruhe Institute of Technology 76131 Karlsruhe Germany
4. Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) 70563 Stuttgart Germany