Browsing by Author "Pennetta, Riccardo"

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    New approaches in quartz-enhanced photoacoustic sensing
    (SPIE, 2015) Sampaolo, Angelo; Patimisco, Pietro; Pennetta, Riccardo; Scamarcio, Gaetano; Tittel, Frank K.
    We report on the design and realization of custom quartz tuning forks with different geometries and sizes aimed to improve the photoacoustic effect in quartz-enhanced photoacoustic (QEPAS) sensor systems. A detailed analysis of the piezoelectric properties in terms of resonance frequencies, quality factors, gas damping was performed.
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    THz Quartz-enhanced photoacoustic sensor for H2S trace gas detection
    (The Optical Society, 2015) Spagnolo, Vincenzo; Patimisco, Pietro; Pennetta, Riccardo; Sampaolo, Angelo; Scamarcio, Gaetano; Vitiello, Miriam S.; Tittel, Frank K.
    We report on a quartz-enhanced photoacoustic (QEPAS) gas sensing system for hydrogen sulphide (H2S) detection. The system architecture is based on a custom quartz tuning fork (QTF) optoacoustic transducer with a novel geometry and a quantum cascade laser (QCL) emitting 1.1 mW at a frequency of 2.913 THz. The QTF operated on the first flexion resonance frequency of 2871 Hz, with a quality factor Q = 17,900 at 20 Torr. The tuning range of the available QCL allowed the excitation of a H2S rotational absorption line with a line-strength as small as S = 1.13·10−22 cm/mol. The measured detection sensitivity is 30 ppm in 3 seconds and 13 ppm for a 30 seconds integration time, which corresponds to a minimum detectable absorption coefficient αmin = 2.3·10−7 cm−1 and a normalized noise-equivalent absorption NNEA = 4.4·10−10W·cm−1·Hz-1/2, several times lower than the values previously reported for near-IR and mid-IR H2S QEPAS sensors.