{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T13:26:56Z","timestamp":1773667616929,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2016,3,25]],"date-time":"2016-03-25T00:00:00Z","timestamp":1458864000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Italian Minister or Research","award":["PON02 00675, PON02 00576 and PON03 \u201cSISTEMA"],"award-info":[{"award-number":["PON02 00675, PON02 00576 and PON03 \u201cSISTEMA"]}]},{"name":"Robert Welch Foundation","award":["grant C-0586"],"award-info":[{"award-number":["grant C-0586"]}]},{"name":"NSF ERC","award":["MIRTHE"],"award-info":[{"award-number":["MIRTHE"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We report on a quartz-enhanced photoacoustic (QEPAS) sensor for methanol (CH3OH) detection employing a novel quartz tuning fork (QTF), specifically designed to enhance the QEPAS sensing performance in the terahertz (THz) spectral range. A discussion of the QTF properties in terms of resonance frequency, quality factor and acousto-electric transduction efficiency as a function of prong sizes and spacing between the QTF prongs is presented. The QTF was employed in a QEPAS sensor system using a 3.93 THz quantum cascade laser as the excitation source in resonance with a CH3OH rotational absorption line located at 131.054 cm\u22121. A minimum detection limit of 160 ppb in 30 s integration time, corresponding to a normalized noise equivalent absorption NNEA = 3.75 \u00d7 10\u221211 cm\u22121W\/Hz\u00bd, was achieved, representing a nearly one-order-of-magnitude improvement with respect to previous reports.<\/jats:p>","DOI":"10.3390\/s16040439","type":"journal-article","created":{"date-parts":[[2016,3,29]],"date-time":"2016-03-29T16:00:28Z","timestamp":1459267228000},"page":"439","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":61,"title":["Improved Tuning Fork for Terahertz Quartz-Enhanced Photoacoustic Spectroscopy"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3790-3767","authenticated-orcid":false,"given":"Angelo","family":"Sampaolo","sequence":"first","affiliation":[{"name":"Dipartimento Interateneo di Fisica, Universit\u00e0 degli studi di Bari Aldo Moro e Politecnico di Bari, Via Amendola 173, Bari I-70126, Italy"},{"name":"Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA"}]},{"given":"Pietro","family":"Patimisco","sequence":"additional","affiliation":[{"name":"Dipartimento Interateneo di Fisica, Universit\u00e0 degli studi di Bari Aldo Moro e Politecnico di Bari, Via Amendola 173, Bari I-70126, Italy"},{"name":"Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2603-7648","authenticated-orcid":false,"given":"Marilena","family":"Giglio","sequence":"additional","affiliation":[{"name":"Dipartimento Interateneo di Fisica, Universit\u00e0 degli studi di Bari Aldo Moro e Politecnico di Bari, Via Amendola 173, Bari I-70126, Italy"}]},{"given":"Miriam","family":"Vitiello","sequence":"additional","affiliation":[{"name":"NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy"}]},{"given":"Harvey","family":"Beere","sequence":"additional","affiliation":[{"name":"Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK"}]},{"given":"David","family":"Ritchie","sequence":"additional","affiliation":[{"name":"Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK"}]},{"given":"Gaetano","family":"Scamarcio","sequence":"additional","affiliation":[{"name":"Dipartimento Interateneo di Fisica, Universit\u00e0 degli studi di Bari Aldo Moro e Politecnico di Bari, Via Amendola 173, Bari I-70126, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2245-7565","authenticated-orcid":false,"given":"Frank","family":"Tittel","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4867-8166","authenticated-orcid":false,"given":"Vincenzo","family":"Spagnolo","sequence":"additional","affiliation":[{"name":"Dipartimento Interateneo di Fisica, Universit\u00e0 degli studi di Bari Aldo Moro e Politecnico di Bari, Via Amendola 173, Bari I-70126, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2016,3,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1007\/s003400050520","article-title":"Gas sensing using terahertz time-domain spectroscopy","volume":"67","author":"Mittleman","year":"1998","journal-title":"Appl. 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