1. College of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
2. Beijing Key Laboratory of Environmentally Harmful Chemicals Analysis, Beijing University of Chemical Technology, Beijing 100029, China
3. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
4. School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo 255049, China
5. State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
6. School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China