1. Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002, China
2. School of Mathematics and Physics, University of South China, Hengyang 421001, China
3. School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
4. Institute of Microscale Optoelectronic, Shenzhen University, Shenzhen 518060, China