1. Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and Engineering South China Normal University Guangzhou 510006 P. R. China
2. Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education) School of Optoelectronic Engineering Chongqing University Chongqing 400044 P. R. China
3. College of Physics and Information Engineering Minnan Normal University Zhangzhou 363000 P. R. China
4. School of Physics and Optoelectronic Engineering Foshan University Foshan 528000 P. R. China