Simultaneous detection of hydrogen sulfide and carbon dioxide based on off‐axis integrated cavity output spectroscopy using a near‐infrared distributed feedback diode laser
Tian Xing, Gang Cheng, Yanan Cao, Jia‐Jin Jason Chen, Kun Liu, Xiaoming Gao
Abstract
Abstract An optical scheme for simultaneous detection of hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ) is demonstrated. A near infrared tunable diode laser operating at 1.578 μm including the absorption lines of H 2 S at 6336.62 cm −1 and CO 2 at 6336.24 cm −1 was used as the light source for spectroscopic measurements of H 2 S and CO 2 . A high‐finesse cavity with a base length of 21 cm and a pair of high reflectivity mirrors with a reflectivity of 99.999% were employed based on off‐axis integrated cavity output spectroscopy. Allan variance analysis shows that the minimum detection limits of 150 ppbv for H 2 S in 170 s averaging time and 1.03 ppmv for CO 2 in 209 s, respectively.