Giglio, MarilenaElefante, AriannaPatimisco, PietroSampaolo, AngeloSgobba, FabrizioRossmadl, HubertMackowiak, VerenaWu, HongpengTittel, Frank K.Dong, LeiSpagnolo, Vincenzo2019-12-122019-12-122019Giglio, Marilena, Elefante, Arianna, Patimisco, Pietro, et al.. "Quartz-enhanced photoacoustic sensor for ethylene detection implementing optimized custom tuning fork-based spectrophone." <i>Optics Express,</i> 27, no. 4 (2019) Optical Society of America: 4271-4280. https://doi.org/10.1364/OE.27.004271.https://hdl.handle.net/1911/107882The design and realization of two highly sensitive and easily interchangeable spectrophones based on custom quartz tuning forks, with a rectangular (S1) or T-shaped (S2) prongs geometry, is reported. The two spectrophones have been implemented in a QEPAS sensor for ethylene detection, employing a DFB-QCL emitting at 10.337 μm with an optical power of 74.2 mW. A comparison between their performances showed a signal-to-noise ratio 3.4 times higher when implementing the S2 spectrophone. For the S2-based sensor, a linear dependence of the QEPAS signal on ethylene concentration was demonstrated in the 5 ppm −100 ppm range. For a 10 s lock-in integration time, an ethylene minimum detection limit of 10 ppb was calculated.eng© 2019 Optical Society of America under the terms of the OSA Open Access Publishing AgreementJournal articleoe-27-4-4271https://doi.org/10.1364/OE.27.004271