Browsing by Author "Mackowiak, Verena"

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    Quartz-enhanced photoacoustic sensor for ethylene detection implementing optimized custom tuning fork-based spectrophone
    (Optical Society of America, 2019) Giglio, Marilena; Elefante, Arianna; Patimisco, Pietro; Sampaolo, Angelo; Sgobba, Fabrizio; Rossmadl, Hubert; Mackowiak, Verena; Wu, Hongpeng; Tittel, Frank K.; Dong, Lei; Spagnolo, Vincenzo
    The 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.
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    Tuning forks with optimized geometries for quartz-enhanced photoacoustic spectroscopy
    (Optical Society of America, 2019) Patimisco, Pietro; Sampaolo, Angelo; Giglio, Marilena; dello Russo, Stefano; Mackowiak, Verena; Rossmadl, Hubert; Cable, Alex; Tittel, Frank K.; Spagnolo, Vincenzo
    We report on the design, realization, and performance of novel quartz tuning forks (QTFs) optimized for quartz-enhanced photoacoustic spectroscopy (QEPAS). Starting from a QTF geometry designed to provide a fundamental flexural in-plane vibrational mode resonance frequency of ~16 kHz, with a quality factor of 15,000 at atmospheric pressure, two novel geometries have been realized: a QTF with T-shaped prongs and a QTF with prongs having rectangular grooves carved on both surface sides. The QTF with grooves showed the lowest electrical resistance, while the T-shaped prongs QTF provided the best photoacoustic response in terms of signal-to-noise ratio (SNR). When acoustically coupled with a pair of micro-resonator tubes, the T-shaped QTF provides a SNR enhancement of a factor of 60 with respect to the bare QTF, which represents a record value for mid-infrared QEPAS sensing.