Intrapulse measurement using a quantum cascade laser coupled with a compact dense pattern multipass absorption cell for carbon dioxide monitoring

Abstract

We demonstrate a mid-infrared spectrometer based on a quantum cascade laser operated in the intrapulse mode coupled with a custom dense pattern multipass cell. Detection in the range of hundreds of ppm to a few percent has been achieved due to a spectral sweep over seven C O 2 absorption lines corresponding to a 2 c m − 1 spectral range. A detection limit of 2.22 ppm (corresponding to an absorption of 1.77 ⋅ 10 − 7 c m − 1 ) for an averaging time of 4 s has been achieved during an in-laboratory characterization. The instrument was used for outdoor measurements of C O 2 in the framework of a massive gas release trial in a military training center. A comparison of measurements with other devices is presented.