1. ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
2. Department of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
3. Institute of Physical Chemistry, Friedrich-Schiller University, 07743 Jena, Germany
4. Missouri University of Science and Technology, Rolla, Missouri 65409, USA
5. Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
6. Physikalisch-Technische Bundesanstalt (PTB), D-38116 Braunschweig, Germany
7. Abbe Center of Photonics, Friedrich-Schiller University, 07745 Jena, Germany
8. ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain