Trace gas detection in ambient air with cw and pulsed QC lasers

Summary form only given.Recently developed quantum-cascade lasers' have been shown to be useful tunable single-frequency light sources for laser-based absorption spectroscopy in the important mid-IR region. In this work, we demonstrate the application of cw and pulsed single-frequency quantum cascade (QC) DFB lasers to the sensitive detection of CH/sub 4/, N/sub 2/O, C/sub 2/H/sub 5/OH (ethanol) and different isotopic species of H/sub 2/O in ambient air will be reported. In order to determine the ethanol concentration from its dense infrared spectrum, a new approach based on a linear correlation technique was applied.