1. Department of Physics and Materials Science, University of Luxembourg, Luxembourg City L-1511, Luxembourg
2. Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
3. Luxembourg Institute of Science and Technology (LIST), Materials Research and Technology (MRT), Advanced Instrumentation for Nano-Analytics (AINA), L-4362 Esch-sur-Alzette, Luxembourg
4. Integrated Systems Laboratory, Department of Information Technology and Electrical Engineering, ETH, Zürich, CH-8092, Zürich, Switzerland
5. Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
6. Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden