1 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
2 Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection, China Petroleum and Chemical Industry Federation (CPCIF), Beijing 100723, China
3 Beijing Key Laboratory of Optical Detection Technology for Oil and Gas, China University of Petroleum, Beijing 102249, China
Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University, and the Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), Tianjin 300072, China