1. Laboratory for Spin Photonics, School of Physics and Electronics, Hunan University, Changsha 410082, China
2. College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China
3. Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China