1. School of Physical Science and Information Technology, Liaocheng University, Liaocheng, Shandong, P. R. China
2. Shandong Provincial Key Laboratory of Optical, Communication Science and Technology, Liaocheng, Shandong, P. R. China
3. School of Physical Science & Technology, Sichuan University, Chengdu, Sichuan, P. R. China
4. Laboratory of Material Chemistry, Institute of Chemical Materials, China Academy of Engineering Physics, Sichuan, P. R. China
5. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan, P. R. China