title: Multiline absorption spectroscopy for methane gas detection.
abstract: A multiline absorption spectroscopy technique was investigated based on the single-line absorption spectroscopy technique. An open-path methane-detecting system was designed. An LED was used as a broadband source, and a Fabry-Perot interferometer whose transmission peaks matched the methane R-branch absorption lines was used to enhance the detectable sensitivity. We demonstrate a minimum-detectable concentration of 7600 +/- 10% ppm (parts per million) with a multiline differential absorption spectroscopy technique and a concentration of 1000 +/- 10% ppm with a multiline wavelength modulation spectroscopy technique.
authors.affiliation: College of Physics, Jilin University, Changchun 130023, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Qu
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Kang
authors.forename: Yun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jin-Yue
authors.initials: JY
authors.lastname: Gao