Mid-Infrared Absorption Spectroscopy for Gas Sensing and Application

Gas sensors play an important role in many applications ranging from chemical processing analysis, medical diagnostics to atmospheric pollution monitoring. The application of sensitive mid-infrared (MIR) absorption spectroscopy technique was reported for multiple gas detection, including methane (CH 4 ), carbon monoxide (CO) and carbon dioxide (CO 2 ). With respect to CH 4 detection, a direct laser absorption spectroscopy (SA-DLAS) architecture was proposed exploiting an interband cascade laser (ICL). With respect to CO detection, a MIR CO system was developed based on a broadband light source and a dual-channel sensing scheme. With respect to CO 2 detection, a MIR monitoring sensor system was implemented by using a single-source dual-channel approach with a compact gas cell. The three demonstrated gas sensor systems were deployed for monitoring atmospheric CH 4 and green house CO 2 concentration levels.