1. Faculty of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, China
2. Key Laboratory of Optoelectronic Technology & Systems, Education Ministry of China, Chongqing University and College of Optoelectronic Engineering, Chongqing University, 400044 Chongqing, China
3. College of Architectural Engineering, Shanxi Institute of Applied Science and Technology, Taiyuan 030031, China