1. Laser Spectroscopy and Sensing Laboratory, Anhui University, Hefei 230601, China
2. School of Mathematics Physics and Finance, Anhui Polytechnic University, Wuhu 241000, China
3. Key Laboratory of Opto-electronic Information Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
4. State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China