Dual interband cascade laser based trace-gas sensor for environmental monitoring

The development of an interband cascade laser (ICL) based spectroscopic trace-gas sensor for the simultaneous detection of two atmospheric trace gases is reported. The sensor performance was evaluated using two ICLs capable of targeting formaldehyde (H₂CO) and ethane (C₂H ₆). Minimum detection limits of 3.5 ppbV for H₂CO and 150 pptV for C₂H₆ was demonstrated with als integration time. The sensor was deployed for field measurements of H₂CO, and laboratory quantification of both formaldehyde and ethane are reported. A cross comparison of the atmospheric concentration data for H₂CO with data collected by a collocated commercial H₂CO sensor employing Hantzsch reaction based fluorometric detection was performed. These results show excellent agreement between these two different approaches for trace-gas quantification. In addition, laboratory experiments for dual gas quantification show accurate, fast response with no crosstalk between the two gas channels.