1. CAS Key Laboratory of Materials for Energy Conversion Department of Materials Science and Engineering University of Science and Technology of China (USTC) Hefei 230026 P. R. China
2. National Synchrotron Radiation Laboratory Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China Hefei 230026 P. R. China
3. Hefei National Laboratory for Physical Sciences at the Microscale Department of Physics University of Science and Technology of China (USTC) Hefei 230026 P. R. China
4. Laser and Optics Research Center Department of Physics United States Air Force Academy CO 80840 USA