Detection of formaldehyde using off-axis integrated cavity output spectroscopy with an interband cascade laser

A continuous-wave, mid-infrared, distributed feedback, interband cascade laser was used to detect and quantify formaldehyde (H2CO) using off-axis, integrated cavity output spectroscopy in gas mixtures containing approximate to 1-25 parts in 10(6) by volume (ppmV) of H2CO. Analysis of the spectral measurements indicates that a H2CO concentration of 150 parts in 10(9) by volume (ppbV) would produce a spectrum with a signal to noise ratio of 3 for a data acquisition time of 3 s. This is a relevant sensitivity level for formaldehyde monitoring of indoor air, occupational settings, and on board spacecraft in long duration missions in particular as the detection sensitivity improves with the square root of the data acquisition time.