1. School of Physics, Hefei University of Technology, Hefei 230009, People’s Republic of China
2. State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, People’s Republic of China
3. Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People’s Republic of China
4. Department of Materials Science & Engineering, City University of Hong Kong, Hong Kong 999077, People’s Republic of China