Pohlkötter, A.A.PohlkötterKöhring, M.M.KöhringWiller, U.U.WillerSchade, W.W.Schade2022-03-042022-03-042010https://publica.fraunhofer.de/handle/publica/22262910.3390/s100908466Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus employing quartz enhanced photoacoustic spectroscopy (QEPAS). With this system a detection limit of 13 ppm is reached with a compact and long term stable setup. Further improvement of the detection limit is possible by adding suitable gases to the sample gas that promote the radiationless de-excitation of the oxygen molecules.en621547journal article