Bonilla Manrique, Óscar ElíasMoser, HaraldMartín Mateos, PedroLendl, BernhardRuiz Llata, Marta2022-10-202022-10-202019-03-14Journal of Sensors, Vol. 2019, Article ID 6437431, March 2019, 7 p.1687-725X1687-7268 (online)https://hdl.handle.net/10016/35912A fast and reliable photoacoustic (PA) sensor for trace gas detection is reported. The sensor is based on a 3D-printed resonant cell in combination with a continuous wave mode-hop-free external cavity quantum cascade laser to rapidly acquire gas absorption data in the midinfrared range. The cell is designed so as to minimize the window PA background at a selected acoustic resonance. The goal is a resonant PA cell capable of detecting the traces of gases using wavelength modulation of the laser source and second harmonic detection. The versatility and enhancement of the limit of detection at sub-ppm levels are investigated by monitoring specific lines of hydrogen sulfide (H2S). The noise-equivalent absorption normalized to laser-beam power and detection bandwidth is 1.07 x 10-8 W cm-1 Hz-1/2 for H2S targeting the absorption line at 1247.2cm-1. These properties make the sensor suitable for various practical sensors for water quality applications.7engCopyright © 2019 Oscar E. Bonilla-Manrique et al.This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedAtribución 3.0 EspañaCellsCytologyGas absorptionGasesHydrogen sulfideLaser beamsQuantum cascade lasersSulfur compoundsSulfur determinationWater qualityAcoustic ResonanceContinuous wave modesLimit of detectionMid-infrared rangeSecond harmonic detectionSulfide detectionsTrace gas detectionWavelength modulation3D printersresearch articleFísicaIngeniería Industrialhttps://doi.org/10.1155/2019/6437431open access164374317Journal of Sensors2019AR/0000023477