Giglio, MarilenaPatimisco, PietroSampaolo, AngeloZifarelli, AndreaBlanchard, RomainPfluegl, ChristianWitinski, Mark F.Vakhshoori, DaryooshTittel, Frank K.Spagnolo, Vincenzo2018-11-192018-11-192018Giglio, Marilena, Patimisco, Pietro, Sampaolo, Angelo, et al.. "Nitrous oxide quartz-enhanced photoacoustic detection employing a broadband distributed-feedback quantum cascade laser array." <i>Applied Physics Letters,</i> 113, (2018) AIP Publishing: https://doi.org/10.1063/1.5049872.https://hdl.handle.net/1911/103358We present a gas sensing system based on quartz-enhanced photoacoustic spectroscopy (QEPAS) employing a monolithic distributed-feedback quantum cascade laser (QCL) array operated in a pulsed mode as a light source. The array consists of 32 quantum cascade lasers emitting in a spectral range from 1190 cm−1 to 1340 cm−1. The optoacoustic detection module was composed of a custom quartz tuning fork with a prong spacing of 1 mm, coupled with two micro-resonator tubes to enhance the signal-to-noise ratio. The QEPAS sensor was validated by detecting the absorption of the P- and R-branches of nitrous oxide. The measurements were performed by switching the array QCLs in sequence while tuning their operating temperature to retrieve the fine structure of the two N2O branches. A sensor calibration was performed, demonstrating a linear responsivity for N2O:N2 concentrations from 1000 down to 200 parts-per-million. With a 10 s lock-in integration time, a detection sensitivity of less than 60 parts-per-billion was achieved permitting the monitoring of nitrous oxide at global atmospheric levels.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttps://doi.org/10.1063/1.5049872