1. National
Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
2. Hefei
National Laboratory for Physical Sciences at the Microscale (HFNL)
and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
3. State
Key Laboratory of Superlattices and Microstructures, Institute of
Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
4. Division
of Physics and Applied Physics, School of Physical and Mathematical
Sciences, Nanyang Technological University, Singapore 637371, Singapore
5. Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
6. Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China