1. National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional Materials Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210023 P. R. China
2. GPL Photonics Laboratory State Key Laboratory of Applied Optics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 P. R. China
3. Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 P. R. China