1. School of Physics and Electronic Engineering
2. Linyi University
3. Linyi 276005
4. P. R. China
5. State Key Lab of Superhard Materials
6. College of Physics
7. Jilin University
8. Changchun 130012
9. Shandong Key Laboratory of Optical Communication Science and Technology
10. School of Physics Science and Information Technology
11. Liaocheng University
12. Liaocheng 252059