1. Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing, China
2. Department of Physics, Beijing Engineering Research Center of Terahertz and Infrared Technology and the Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Capital Normal University, Beijing, China
3. School of Science, Minzu University of China, Beijing, China