Trace gas detection based on photoacoustic spectroscopy in 3-D printed gas cell

A novel photoacoustic spectroscopy gas sensor based on a micro-resonator has been developed. The photoacoustic cell was designed and fabricated using 3-D printing and the photoacoustic cell volume was compressed significantly. This design greatly reduces the time of manufacturing the micro-resonator and the weight was lighter compared to traditional cells. Furthermore, the acoustic pressure distribution in the 3-D printed photoacoustic cell was analyzed by COMSOL Multiphysics software, which indicated that the strongest acoustic pressure occurred in the middle of the resonant cavity. The performance of the sensor was evaluated by detection of CH4 at normal atmospheric pressure used a near infrared distributed feedback laser emitted at 1653 nm. The characteristic of the photoacoustic signal under different pressures was also investigated. An Allan variance shows that the 3-D printed photoacoustic spectroscopy sensor has the detection limit of 1.44 ppmv (3σ) for CH4 detection at about 200 s integration time.

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High Sensitivity Continuous Monitoring of Chloroform Gas by Using Wavelength Modulation Photoacoustic Spectroscopy in the Near-Infrared Range

Applied Sciences ◽

10.3390/app11156992 ◽

2021 ◽

Vol 11 (15) ◽

pp. 6992

Author(s):

Tie Zhang ◽

Yuxin Xing ◽

Gaoxuan Wang ◽

Sailing He

Keyword(s):

Photoacoustic Spectroscopy ◽

Continuous Monitoring ◽

Near Infrared ◽

Resonant Cavity ◽

High Sensitivity ◽

Industrial Applications ◽

Detection Sensitivity ◽

Infrared Range ◽

Wavelength Modulation ◽

Linear Coefficient

An optical system for gaseous chloroform (CHCl3) detection based on wavelength modulation photoacoustic spectroscopy (WMPAS) is proposed for the first time by using a distributed feedback (DFB) laser with a center wavelength of 1683 nm where chloroform has strong and complex absorption peaks. The WMPAS sensor developed possesses the advantages of having a simple structure, high-sensitivity, and direct measurement. A resonant cavity made of stainless steel with a resonant frequency of 6390 Hz was utilized, and eight microphones were located at the middle of the resonator at uniform intervals to collect the sound signal. All of the devices were integrated into an instrument box for practical applications. The performance of the WMPAS sensor was experimentally demonstrated with the measurement of different concentrations of chloroform from 63 to 625 ppm. A linear coefficient R2 of 0.999 and a detection sensitivity of 0.28 ppm with a time period of 20 s were achieved at room temperature (around 20 °C) and atmosphere pressure. Long-time continuous monitoring for a fixed concentration of chloroform gas was carried out to demonstrate the excellent stability of the system. The performance of the system shows great practical value for the detection of chloroform gas in industrial applications.

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Application of Micro Quartz Tuning Fork in Trace Gas Sensing by Use of Quartz-Enhanced Photoacoustic Spectroscopy

Sensors ◽

10.3390/s19235240 ◽

2019 ◽

Vol 19 (23) ◽

pp. 5240 ◽

Cited By ~ 2

Author(s):

Haoyang Lin ◽

Zhao Huang ◽

Ruifeng Kan ◽

Huadan Zheng ◽

Yihua Liu ◽

...

Keyword(s):

Photoacoustic Spectroscopy ◽

Tuning Fork ◽

Gas Sensing ◽

Modulation Depth ◽

Quartz Tuning Fork ◽

Acoustic Resonance ◽

Photoacoustic Signal ◽

Integration Time ◽

Sampling Volume ◽

Qepas Sensor

A novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a micro quartz tuning fork (QTF) is reported. As a photoacoustic transducer, a novel micro QTF was 3.7 times smaller than the usually used standard QTF, resulting in a gas sampling volume of ~0.1 mm3. As a proof of concept, water vapor in the air was detected by using 1.39 μm distributed feedback (DFB) laser. A detailed analysis of the performance of a QEPAS sensor based on the micro QTF was performed by detecting atmosphere H2O. The laser focus position and the laser modulation depth were optimized to improve the QEPAS excitation efficiency. A pair of acoustic micro resonators (AmRs) was assembled with the micro QTF in an on-beam configuration to enhance the photoacoustic signal. The AmRs geometry was optimized to amplify the acoustic resonance. With a 1 s integration time, a normalized noise equivalent absorption coefficient (NNEA) of 1.97 × 10−8 W·cm−1·Hz−1/2 was achieved when detecting H2O at less than 1 atm.

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Fiber-Coupled Quartz-Enhanced Photoacoustic Spectroscopy System for Methane and Ethane Monitoring in the Near-Infrared Spectral Range

Molecules ◽

10.3390/molecules25235607 ◽

2020 ◽

Vol 25 (23) ◽

pp. 5607

Author(s):

Giansergio Menduni ◽

Fabrizio Sgobba ◽

Stefano Dello Russo ◽

Ada Cristina Ranieri ◽

Angelo Sampaolo ◽

...

Keyword(s):

Photoacoustic Spectroscopy ◽

Near Infrared ◽

Integration Time ◽

Vapor Concentration ◽

Acoustic Detection ◽

Near Ir ◽

Qepas Signal ◽

Infrared Spectral ◽

Lock In ◽

Minimum Detection Limits

We report on a fiber-coupled, quartz-enhanced photoacoustic spectroscopy (QEPAS) near-IR sensor for sequential detection of methane (CH4 or C1) and ethane (C2H6 or C2) in air. With the aim of developing a lightweight, compact, low-power-consumption sensor suitable for unmanned aerial vehicles (UAVs)-empowered environmental monitoring, an all-fiber configuration was designed and realized. Two laser diodes emitting at 1653.7 nm and 1684 nm for CH4 and C2H6 detection, respectively, were fiber-combined and fiber-coupled to the collimator port of the acoustic detection module. No cross talk between methane and ethane QEPAS signal was observed, and the related peak signals were well resolved. The QEPAS sensor was calibrated using gas samples generated from certified concentrations of 1% CH4 in N2 and 1% C2H6 in N2. At a lock-in integration time of 100 ms, minimum detection limits of 0.76 ppm and 34 ppm for methane and ethane were achieved, respectively. The relaxation rate of CH4 in standard air has been investigated considering the effects of H2O, N2 and O2 molecules. No influence on the CH4 QEPAS signal is expected when the water vapor concentration level present in air varies in the range 0.6–3%.

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The Absorption Behavior of Water and Some Organic Liquids in the Near Infrared Studied by Photoacoustic Spectroscopy

Zeitschrift für Naturforschung A ◽

10.1515/zna-1984-1217 ◽

1984 ◽

Vol 39 (12) ◽

pp. 1242-1249 ◽

Cited By ~ 1

Author(s):

U. Haas ◽

H. Seiler

Keyword(s):

Photoacoustic Spectroscopy ◽

Near Infrared ◽

Modulation Frequency ◽

Incident Light ◽

Photoacoustic Signal ◽

Liquid Structure ◽

Organic Liquids ◽

Absorption Bands ◽

Expected Frequency ◽

Hydroxyl Absorption

The optical absorption of water and some organic liquids [CH3OH, CH3OD, CD3OD, C2H5OH, C4H9OH, (CH3)2CO, (C2H5)2O and C6H6] has been investigated in the near infrared by photoacoustic spectroscopy. Characteristical absorption bands of combinations and overtones of strong infrared fundamental vibrations are observed and can be used for qualitative analysis of these liquids. The amplitude of the photoacoustic signal shows an f-1-dependence of the modulation frequency f of the incident light for all absorption signals, except for the hydroxyl absorption bands of water and the alcohols. The deviation of the expected frequency dependence points to a modification of the liquid structure toward the surface of the liquid-gas boundary.

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Advances in fiber‐based quartz enhanced photoacoustic spectroscopy for trace gas sensing

Microwave and Optical Technology Letters ◽

10.1002/mop.32841 ◽

2021 ◽

Author(s):

Wei Feng ◽

Yanchen Qu ◽

Yachen Gao ◽

Yufei Ma

Keyword(s):

Photoacoustic Spectroscopy ◽

Gas Sensing ◽

Trace Gas ◽

Trace Gas Sensing

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Photoacoustic spectroscopy for detection of trace C2H2 using ellipsoidal photoacoustic cell

Optics Communications ◽

10.1016/j.optcom.2021.126764 ◽

2021 ◽

Vol 487 ◽

pp. 126764

Author(s):

Chu Zhang ◽

Qiaoyun Wang ◽

Xiangyu Yin

Keyword(s):

Photoacoustic Spectroscopy ◽

Photoacoustic Cell

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Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-69-2007 ◽

2007 ◽

Vol 7 (1) ◽

pp. 69-79 ◽

Cited By ~ 20

Author(s):

T. Wagner ◽

S. Beirle ◽

T. Deutschmann ◽

M. Grzegorski ◽

U. Platt

Keyword(s):

Optical Absorption ◽

Absorption Spectroscopy ◽

Spectral Range ◽

Near Infrared ◽

Vegetation Type ◽

Differential Optical Absorption Spectroscopy ◽

Trace Gas ◽

Satellite Monitoring ◽

Optical Absorption Spectroscopy ◽

Vegetation Types

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm) reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms). The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

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