1. State Key Laboratory for Mesoscopic Physics Department of Physics Peking University Beijing 100871 P. R. China
2. Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 P. R. China
3. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Zhuhai 519000 P. R. China
4. Department of Electrical Engineering The Pennsylvania State University University Park PA 16802 USA
5. Department of Biomedical Engineering Penn State Material Research Institute The Pennsylvania State University University Park PA 16802 USA
6. Biomedical Engineering and Electrical & Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
7. Peking University Yangtze Delta Institute of Optoelectronics Nantong Jiangsu 226010 P. R. China