Off-beam quartz-enhanced photoacoustic spectroscopy

Liu, Kun; Guo, Xiaosong; Yi, Hongming; Chen, Weidong; Zhang, Weijun; Gao, Xiaoming

doi:10.1364/ol.34.001594

Cited by 209 publications

(101 citation statements)

References 7 publications

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“…The acoustic system composed of a tuning fork and an acoustic resonator is referred to as a QEPAS spectrophone. The acoustic resonators used so far consisted of two metallic tubes aligned perpendicular to the QTF plane (dual-tube spectrophone) in an on-beam QEPAS configuration, or a single tube aligned parallel or in proximity to the QTF in the so-called off-beam QEPAS configuration [6][7][8][9]. In an off-beam QEPAS configuration, the tube length is determined by the QTF resonance mode frequency, since the resonant acoustic pressure antinode must be located at the center of the tube.…”

Section: Introductionmentioning

confidence: 99%

Quartz–enhanced photoacoustic spectrophones exploiting custom tuning forks: a review

Patimisco

Sampaolo

Zheng

et al. 2016

Advances in Physics: X

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A detailed review on the design and realization of spectrophones exploiting custom quartz tuning forks (QTFs) aimed to applications of quartz-enhanced photoacoustic (QEPAS) trace-gas sensors is reported. A spectrophone consists of a custom QTF and a micro-resonator system based on a pair of tubes (dual-tube configuration) or a single-tube. The influence of the QTF and resonator tube geometry and sizes on the main spectrophone parameters determining the QEPAS performance, specifically the quality factor Q and the resonance frequency has been investigated. Results obtained previously are reviewed both when the QTF vibrates on the fundamental and the first overtone flexural modes. We also report new results obtained with a novel QTF design. Finally, we compare the QEPAS performance of all the different spectrophone configurations reported in terms of signal-tonoise ratio and provide relevant and useful conclusions from this analysis.

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Section: Introductionmentioning

confidence: 99%

Quartz–enhanced photoacoustic spectrophones exploiting custom tuning forks: a review

Patimisco

Sampaolo

Zheng

et al. 2016

Advances in Physics: X

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“…This sensor is based on Quartz Enhanced Photo Acoustic Spectroscopy (QEPAS) [3], which is one of the many forms of infrared absorption spectroscopy, particularly interesting for allowing the extremely small size and reduced costs of its analysis cell. While QEPAS sensors generally operate in a narrow spectral window around the sharp absorption peak of a given small-mass molecule [4][5][6][7][8][9][10][11], our sensor uses a widely tunable laser source to scan a vast portion of the spectrum, to detect and recognize the fingerprints of a number of relatively complex molecules with broad absorption patterns. A few examples of this approach are reported in the literature [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Quartz Enhanced Photoacoustic Spectroscopy for Detection of Improvised Explosive Devices and Precursors

Viola

Liberatore

Luciani

et al. 2016

Advances in Optical Technologies

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A compact portable and standalone point sensor has been developed for the detection and identification of precursors of improvised explosive devices (IEDs) and to be part of a network of sensors for the discovery of hidden bomb factories in homeland security applications. The sensor is based on quartz enhanced photoacoustic spectroscopy (QEPAS), and it implements a broadly tunable external cavity quantum cascade laser source (EC-QCL). It makes use of an optical cell purposely designed with a miniaturized internal volume, to achieve fast response and high sensitivity, and that can also be heated to improve sensitivity towards less volatile compounds. The sensor has been assembled and successfully tested in the lab with several compounds, including IED's precursors such as acetone, nitromethane, nitric acid, and hydrogen peroxide. The identification capability and limits of detection near the ppm level have been estimated for all these compounds.

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“…Further enhancements of the QEPAS signal is achieved by means of a micro-resonator (mR), if the incident sound waves are confined in the mR. A typical acoustic mR consists of two thin tubes aligned either perpendicular or parallel to the QTF plane. Different QEPAS configurations have been demonstrated, such as on-beam [4,6], off-beam [7], modulation cancellation [8], and evanescent wave QEPAS [9]. In Fig.…”

Section: Introductionmentioning

confidence: 99%