High-resolution frequency-domain spectroscopy for water vapor with coherent and continuous terahertz wave

Cunjun Ruan; Deyin Kong; Jun Dai; Kanglong Chen; Sujie Guo; Xiaojun Wu

doi:10.3788/COL201917.073001

Journals >Chinese Optics Letters >Volume 17 >Issue 7 >Page 073001 > Article

Chinese Optics Letters
Vol. 17, Issue 7, 073001 (2019)

High-resolution frequency-domain spectroscopy for water vapor with coherent and continuous terahertz wave

Cunjun Ruan^1、2、*, Deyin Kong¹, Jun Dai¹, Kanglong Chen¹, Sujie Guo¹, and Xiaojun Wu¹

Author Affiliations

¹School of Electronic and Information Engineering, Beihang University, Beijing 100191, China

²Beijing Key Laboratory for Microwave Sensing and Security Applications, Beihang University, Beijing 100191, China

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DOI: 10.3788/COL201917.073001 Cite this Article Set citation alerts

Cunjun Ruan, Deyin Kong, Jun Dai, Kanglong Chen, Sujie Guo, Xiaojun Wu. High-resolution frequency-domain spectroscopy for water vapor with coherent and continuous terahertz wave[J]. Chinese Optics Letters, 2019, 17(7): 073001 Copy Citation Text

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Abstract

High-resolution frequency-domain spectroscopy (FDS) is set up using a coherent and continuous wave terahertz (THz) emitter and receiver. THz waves are generated and detected by two photomixers with two distributed feedback (DFB) lasers. Atmospheric water vapor with different relative humidity is systematically investigated by the FDS. A high-frequency resolution of ～14 MHz is obtained with the help of Hilbert transformation, leading to a well resolved and distinct transmittance characterization of water vapor. Compared with conventional THz time-domain spectroscopy, the high-resolution continuous wave THz spectrometer is one of the most practical systems in gas-phase molecular sensing, identification, and monitoring.