Author Affiliations

Jura Rensberg,¹ Shuyan Zhang,² Alexander S. McLeod,³ Christian Schwarz,¹ Michael Goldflam,³ Ronny Nawrodt,¹ Mengkun Liu,^3,4 Jochen Kerbusch,⁵ You Zhou,² Shriram Ramanathan,² D. N. Basov,³ Federico Capasso,² Carsten Ronning,¹ and Mikhail A. Kats^2,6

¹Institute for Solid State Physics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany

²School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

³Department of Physics, University of California - San Diego, La Jolla, California 92093, USA

⁴Department of Physics, Stony Brook University, Stony Brook, New York 11794, USA

⁵Institute of Ion Beam Physics and Materials Research, Helmholts-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany

⁶Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA