1. Institute of Crystalline Materials, Shanxi University, Taiyuan, Shanxi 030006, P. R. China
2. College of Chemistry, Key Laboratory of Interface Science and Engineering in Advanced Material, Ministry of Education, Taiyuan University of Technology, Taiyuan, Shanxi 030024, P. R. China
3. Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan, Shanxi 030006, P. R. China