1. ICFO−Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
2. Center for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
3. Nanophotonics and Metrology Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), Station 11, CH 1015, Lausanne, Switzerland
4. POLIMA−Center for Polariton-Driven Light−Matter Interactions, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
5. Danish Institute for Advanced Study, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
6. ICREA−Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain