Physics Department, South China University of Technology, Guangzhou, China;College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, China
Physics Department, South China University of Technology, Guangzhou, China;College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, China
Copyright © 2016 Jing Huang, Jianquan Yao et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.