Photoacoustic gas sensing with a commercial external cavity-quantum cascade laser at 10.5 μm

• We report the implementation of a commercial EC-QCL in a photoacoustic spectrometer.
• This spectrometer enables measurements at 10.5 μm on spectral range up to 60 cm−1.
• The Mode-Hop Free tuning enables to detect small molecules such as carbon dioxide.
• The wide tuning range permits the detection of complex molecules such as butane.

We report the implementation of a commercial external cavity-quantum cascade laser emitting at 10.5 μm in a photoacoustic spectrometer. This spectrometer enables measurements on broad spectral range up to 60 cm−1 which means that spectra of complex molecules can be recorded as well as a whole absorption band of a small molecule. The wide tuning range of the source of this photoacoustic spectrometer demonstrates the possibility to detect small and complex molecules such as carbon dioxide and butane.