1. State Key Laboratory of Pulsed Power Laser Technology Anhui Laboratory of Advanced Laser Technology National University of Defense Technology Hefei 230037 P.R. China
2. Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and Nanotechnology Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 P.R. China
3. Anhui Institute of Optics and Fine Mechanics (AIOFM) Chinese Academy of Sciences Hefei 230031 P.R. China