1. Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education; Wuhan University; Wuhan 430072 China
2. Beijing National Laboratory for Molecular Sciences; Key Laboratory of Organic Solids; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100080 China
3. Department of Electronic & Computer Engineering; The Hong Kong University of Science & Technology; Hong Kong SAR China
4. National Laboratory for Infrared Physics; Shanghai Institute of Technical Physics; Chinese Academy of Sciences; Shanghai 200083 China
5. Synergetic Innovation Center of Quantum Information & Quantum Physics; University of Science and Technology of China; Hefei Anhui 230026 China