1. Institute of Thin Films and Physics of Nanostructures Bielefeld University Universitätsstrasse 25 D‐33165 Bielefeld Germany
2. Center for Hybrid Nanostructures Hamburg University Luruper Chaussee D‐22761 Hamburg Germany
3. The Hamburg Center for Ultrafast Imaging Hamburg University Luruper Chausee 149 D‐22761 Hamburg Germany
4. Institute of Physical Chemistry Hamburg University Grindelallee 117 D‐20146 Hamburg Germany
5. Institute of Advanced Ceramics Hamburg University of Technology Denickestrasse 15 D‐21073 Hamburg Germany
6. Fraunhofer‐CAN Grindelallee 117 D‐20146 Hamburg Germany