1. School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China
2. Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China
3. School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 P. R. China
4. Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology Guilin 541004 China