1. MoE Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Beijing, China
2. State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, China
3. Key Laboratory of Intelligent Manufacturing Technology, Ministry of Education, College of Engineering, Shantou University, Shantou, China
4. Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA