1. Department of Physics, East China Normal University, Shanghai 200241, China
2. Key Laboratory of Polar Materials and Devices (MOE), East China Normal University, Shanghai 200241, China
3. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
4. Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China