1. Graphene
Labs, Fondazione Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
2. State
Key Laboratory of Infrared Physics, Shanghai Institute of Technical
Physics, Chinese Academy of Sciences, Shanghai, People’s Republic of China
3. Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China
4. Department
of Physics, University of Calabria, via Ponte Bucci, cubo 31/C, 87036 Rende, Cosenza, Italy