1. College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
2. College of Physics and Electronic Information Engineering, Neijiang Normal University, Neijiang 641112, China
3. Previously with Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu 610200, China
4. Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621999, China
5. Municipal Key Laboratory of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300350, China
6. Engineering Research Center of Thin Film Optoelectronics Technology, Ministry of Education, Nankai University, Tianjin 300350, China