1. School of Science, North University of China, No. 3, Xueyuan Road, Taiyuan, Shanxi 030051, China
2. State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, and Key Laboratory for Thin Film and Microfabrication Technology of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China
3. Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China