1. Department of Physics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, GR157 80 Athens, Greece
2. POLIMA—Center for Polariton-Driven Light–Matter Interactions, University of Southern Denmark, Campusvej 55, DK5230 Odense, Denmark
3. Department of Materials Science, University of Patras, GR265 04 Patras, Greece