1. Department of Physics of Normal College, Shenzhen University, Shenzhen 518060, China
2. State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430074, China
3. Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
4. CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, China