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O. Bonilla-Manrique, H. Moser, P. Martin-Mateos, B. Lendl, M. Ruiz-Llata:
"Hydrogen Sulfide Detection in the Midinfrared Using a 3D-Printed Resonant Gas Cell";
Journal of Sensors, 2019 (2019), 6437431; 1 - 7.

Afastandreliablephotoacoustic(PA)sensorfortracegasdetectionisreported.Thesensorisbasedona3D-printedresonantcellin 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 107×10-8 Wcm-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.