1. Department of Physics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, GR-15780 Athens, Greece
2. POLIMA—Center for Polariton-Driven Light–Matter Interactions, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
3. Department of Materials Science, University of Patras, GR-26504 Patras, Greece