Hollow waveguide enhanced dimethyl sulfide sensor based on a 3.3 μm interband cascade laser

Detection of dimethyl sulfide (CH3SCH3) is significant for protection of environmental atmosphere and safety of industrial and agricultural production. A tunable laser absorption spectroscopy (TLAS)based dimethyl sulfide sensor, employing a 5 m hollow waveguide (HWG) as a gas cell and a 3.37 mu m, continuous -wave, DFB, room temperature interband cascade laser (ICL), is reported. Wavelength modulation spectroscopy second harmonic normalized by the first harmonic (WMS 2f/1f) technique is used to retrieve the concentration of dimethyl sulfide with high sensitivity. The sensor has a mass of similar to 5 kg and consumes similar to 50 W of electrical power. The sensor performance evaluation shows that it has a sensitivity of 20 ppb with time resolution of 1s, a rapid rise time and fall time of similar to 27 s and similar to 25 s and a measurement precision of 21 ppb. Furthermore, an Allan deviation analysis shows that the detection limit can reach 2.8 ppb for a 125 s averaging time. Overall, the reported sensor can be applied to environmental monitoring, industrial production and the biomedicine field for dimethyl sulfide detection. (C) 2017 Elsevier B.V. All rights reserved.