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