1. Department of Opto-electronics
and Information Engineering, School of Precision Instruments and Opto-electronics
Engineering, and Key Laboratory of Optoelectronic Information Technology,
Ministry of Education, Tianjin University, Tianjin 300072, People’s Republic of China
2. Department of Electronic Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon,
Hong Kong, People’s Republic of China