Author Affiliations

Georg Enzian,^1,2,3 John J. Price,^1,2,4 Lars Freisem,^1,2 Magdalena Szczykulska,² Joshua Nunn,^2,4 Ian A. Walmsley,^1,2 Jonathan Silver,⁵ Leonardo Del Bino,^5,6 Shuangyou Zhang,^5,6 Pascal Del’Haye,^5,6 Jiri Janousek,⁷ Ben C. Buchler,⁷ Ping Koy Lam,⁷ and Michael R. Vanner^*,1,2

¹QOLS, Blackett Laboratory, Imperial College London, SW7 2AK, United Kingdom

²Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, United Kingdom

³Niels Bohr Institute, University of Copenhagen, Denmark

⁴Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, United Kingdom

⁵National Physical Laboratory, Teddington, TW11 0LW, United Kingdom

⁶Max Planck Institute for the Science of Light, Erlangen, 91058 Germany

⁷Research School of Physics and Engineering, Australian National University, Canberra, Australia

^*Corresponding author: m.vanner@imperial.ac.uk