NO2 dynamics of an Ar/Air plasma jet investigated by in situ quantum cascade laser spectroscopy at atmospheric pressure

Abstract

In this work, quantum cascade laser (QCL) absorption spectroscopy was used to investigate the nitric dioxide (NO2) production dynamics at ambient conditions. For the first time, QCL detection of NO2 and NO was used at ambient conditions in order to remain close to the conditions that are present in the application of plasma jets in open atmosphere. For the investigations, the plasma jet was placed inside an open multi-pass cell. The detection limit of the setup was 20 ppb for NO2 and similar for nitric oxide (NO). Since the effective production of NO was below the detection limit, further investigations of the NO density were performed with optical emission spectroscopy. © 2014 IOP Publishing Ltd.