1. School of Physics, Beihang University, Beijing 100191, China
2. Beijing Engineering Research Center of Laser Technologyd, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
3. College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials of Education Ministry of China, Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China
4. Department of Physics, Department of Materials Science and Engineering, and Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China