1. Department of Physics, Korea Advanced Institute of Science and Technology, Daehak-Ro 291, Daejeon 34141, Republic of Korea
2. POLIMA─Center for Polariton-Driven Light-Matter Interactions, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
3. Ginzton Laboratory, Stanford University, 348 Via Pueblo, Stanford, California 94305, United States
4. Danish Institute for Advanced Study, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark