1. Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China
2. College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
3. School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China