P. J. Heikkinen, A. Casey, L. V. Levitin, X. Rojas, A. Vorontsov, P. Sharma, N. Zhelev, J. M. Parpia and J.Saunders Submitted to Nature Physics, August 2019 200nm_slab_natphys_submission.pdf 200nm_slab_natphys_SI_submission.pdf