Author Affiliations

C. Y. Wang,^1,* L. Diehl,² A. Gordon,³ C. Jirauschek,³ F. Capasso,² F. Kärtner,³ A. Belyanin,⁴ D. Bour,⁵ S. Corzine,⁵ G. Höfler,⁵ M. Troccoli,² P. Grant,⁶ H. C. Liu,⁶ and J. Faist⁷

¹Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

²Division of Engineering & Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

³Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

⁴Department of Physics, Texas A&M University, College Station, Texas 77843, USA

⁵Agilent Technologies, Palo Alto, California, USA

⁶National Research Council, Ottawa, Canada

⁷Institute of Physics, University of Neuchâtel, CH-2000 Neuchâtel, Switzerland

^*Corresponding author: wang@fas.harvard.edu