scholarly journals Near-Infrared Quartz-Enhanced Photoacoustic Sensor for H2S Detection in Biogas

2019 ◽  
Vol 9 (24) ◽  
pp. 5347
Author(s):  
Fagang Zhao ◽  
Yutong Gao ◽  
Lin Yang ◽  
Yuqing Yan ◽  
Jiashi Li ◽  
...  
Keyword(s):  
Laser Power ◽  
Near Infrared ◽  
Tuning Fork ◽  
Signal Amplitude ◽  
Quartz Tuning Fork ◽  
Detection Sensitivity ◽  
Integration Time ◽  
Optical Source ◽  
H2s Detection ◽  
Qepas Sensor

A quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for H2S detection operating in near-infrared spectral range is reported. The optical source is an erbium-doped fiber amplified laser with watt-level optical power. The QEPAS spectrophone is composed of a quartz tuning fork with a resonance frequency of 7.2 kHz, a quality factor of 8500, and a distance between prongs of 800 µm, and two tubes with a radius of 1.3 mm and a length of 23 mm acting as an organ pipe resonator. With this spectrophone geometry, the photothermal noise contribution of the spectrophone was removed and the theoretical thermal noise level was achieved. The position of both tubes with respect to custom quartz tuning fork has been investigated as a function of signal amplitude, Q-factor, and noise of the QEPAS sensor when a high-power laser was used. Benefit from the linearity of the QEPAS signal to the excitation laser power, a detection sensitivity of 330 ppb for H2S detection was achieved at atmospheric pressure and room temperature, when the laser power was 1.6 W and the signal integration time was set to 300 ms, corresponding to a normalized noise equivalent absorption of 3.15 × 10−9 W cm−1/(Hz)1/2. The QEPAS sensor was then validated by measuring H2S in a biogas sample.

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

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5240 ◽  
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.

scholarly journals Acoustic Detection Module Design of a Quartz-Enhanced Photoacoustic Sensor

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1093 ◽  
Author(s):  
Tingting Wei ◽  
Hongpeng Wu ◽  
Lei Dong ◽  
Frank Tittel
Keyword(s):  
Near Infrared ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Acoustic Detection ◽  
Numerous Application ◽  
Mid Infrared ◽  
Module Design ◽  
Laser Sources ◽  
Infrared Laser Sources ◽  
Reliability And Robustness

This review aims to discuss the latest advancements of an acoustic detection module (ADM) based on quartz-enhanced photoacoustic spectroscopy (QEPAS). Starting from guidelines for the design of an ADM, the ADM design philosophy is described. This is followed by a review of the earliest standard quartz tuning fork (QTF)-based ADM for laboratory applications. Subsequently, the design of industrial fiber-coupled and free-space ADMs based on a standard QTF for near-infrared and mid-infrared laser sources respectively are described. Furthermore, an overview of the latest development of a QEPAS ADM employing a custom QTF is reported. Numerous application examples of four QEPAS ADMs are described in order to demonstrate their reliability and robustness.

scholarly journals Quartz Tuning Fork Resonance Tracking and application in Quartz Enhanced Photoacoustics Spectroscopy

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5565 ◽  
Author(s):  
Roman Rousseau ◽  
Nicolas Maurin ◽  
Wioletta Trzpil ◽  
Michael Bahriz ◽  
Aurore Vicet
Keyword(s):  
Tuning Fork ◽  
Beat Frequency ◽  
Quartz Tuning Fork ◽  
Characterization Methods ◽  
Force Microscopy ◽  
Atomic Force ◽  
Signal Drift ◽  
Environment Temperature ◽  
Photo Acoustic Spectroscopy ◽  
Qepas Sensor

The quartz tuning fork (QTF) is a piezoelectric transducer with a high quality factor that was successfully employed in sensitive applications such as atomic force microscopy or Quartz-Enhanced Photo-Acoustic Spectroscopy (QEPAS). The variability of the environment (temperature, humidity) can lead to a drift of the QTF resonance. In most applications, regular QTF calibration is absolutely essential. Because the requirements vary greatly depending on the field of application, different characterization methods can be found in the literature. We present a review of these methods and compare them in terms of accuracy. Then, we further detail one technique, called Beat Frequency analysis, based on the transient response followed by heterodyning. This method proved to be fast and accurate. Further, we demonstrate the resonance tracking of the QTF while changing the temperature and the humidity. Finally, we integrate this characterization method in our Resonance Tracking (RT) QEPAS sensor and show the significant reduction of the signal drift compared to a conventional QEPAS sensor.

scholarly journals Standoff pump-probe photothermal detection of hazardous chemicals

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ramesh C. Sharma ◽  
Subodh Kumar ◽  
Abhishek Parmar ◽  
Mohit Mann ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Homeland Security ◽  
Tuning Fork ◽  
Spectral Band ◽  
Quartz Tuning Fork ◽  
Detection Sensitivity ◽  
Hazardous Chemicals ◽  
Liquid Form ◽  
Pump Probe ◽  
Pump And Probe ◽  
Infrared Spectral

Abstract A novel pump-probe Photothermal methodology using Quartz Tuning Fork (QTF) detector has been demonstrated for the first time. A tunable mid-IR Quantum Cascade Laser (QCL) and a CW fixed wavelength visible laser have been used as the pump and probe beam respectively. The developed Photothermal (PT) technique is based on Quartz Tuning Fork (QTF) detector for the detection of hazardous/explosive molecules adsorbed on plastic surface and also in aerosols form. PT spectra of various trace molecules in the fingerprinting mid- infrared spectral band 7–9 µm from distance of 25 m have been recorded. The PT spectra of explosives RDX, TNT and Acetone have been recorded at very low quantities. Acetone is the precursor of explosive Tri-Acetone Tri-Phosphate (TATP). The experimentations using pump and probe lasers, exhibit detection sensitivity of less than 5 μg/cm2 for RDX, TNT powders and of ~ 200 nl quantity for Nitrobenzene (NB) and Acetone (in liquid form) adsorbed on surfaces, from a distance of ~ 25 m. The sensitivity of the same order achieved from a distance of 15 m by using only a mid-IR tunable pump laser coupled to QTF detector. Thus the pump-probe PT technique is more sensitive in comparison to single tunable QCL pump beam technique and it is better suited for standoff detection of hazardous chemicals for homeland security as well as for forensic applications.

scholarly journals HCl ppb-level detection based on QEPAS sensor using a low resonance frequency quartz tuning fork

2016 ◽  
Vol 233 ◽  
pp. 388-393 ◽  
Author(s):  
Yufei Ma ◽  
Ying He ◽  
Xin Yu ◽  
Cheng Chen ◽  
Rui Sun ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Qepas Sensor

Photoacoustic spectroscopy telemetry of airport dangerous goods

2019 ◽  
Vol 33 (02) ◽  
pp. 1950007
Author(s):  
Zhouqiang Zhang ◽  
Shuhai Jia ◽  
Guangshen Xu ◽  
Yabin Cao
Keyword(s):  
Absorption Coefficient ◽  
Diode Laser ◽  
Infrared Absorption ◽  
Photoacoustic Spectroscopy ◽  
Near Infrared ◽  
Tuning Fork ◽  
Laser Light ◽  
Quartz Tuning Fork ◽  
Dangerous Goods ◽  
Future Work

A novel photoacoustic spectroscopy telemetry method of detecting trace acetylene gas using a quartz tuning fork is reported. A 1532-nm CW-DFB, fiber-coupled diode laser with power of 12 mW was used as the excitation source while an astronomical telescope was used to collect laser light scattered on the surface of the detected object at a distance of 6 m and the photoacoustic spectroscopy of acetylene was performed. The detection results are consistent with the standard near-infrared absorption coefficient of acetylene. This study provides a new direction for research in photoacoustic spectroscopy telemetry. Future work will quantitatively analyze acetylene gas.

scholarly journals Enhanced near-infrared QEPAS sensor for sub-ppm level H2S detection by means of a fiber amplified 1582 nm DFB laser

2015 ◽  
Vol 221 ◽  
pp. 666-672 ◽  
Author(s):  
Hongpeng Wu ◽  
Lei Dong ◽  
Huadan Zheng ◽  
Xiaoli Liu ◽  
Xukun Yin ◽  
...  
Keyword(s):  
Near Infrared ◽  
Dfb Laser ◽  
Ppm Level ◽  
H2s Detection ◽  
Qepas Sensor

Multi-Site Cr3+ Occupation Related Broadband NIR Luminescence in Cr3+-doped Li3Mg2NbO6

CrystEngComm ◽  
2021 ◽  
Author(s):  
Fen Xiao ◽  
Chengning Xie ◽  
Shikun Xie ◽  
Rongxi Yi ◽  
Huiling Yuan ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Luminescent Materials ◽  
Optical Source ◽  
Nir Emission ◽  
Nir Luminescence

Broadband near infrared (NIR) luminescent materials have attracted great attention recently for the advance smart optical source of NIR spectroscopy. In this work, a broadband NIR emission from 650 nm...

scholarly journals Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 286
Author(s):  
Ashfaq Ali ◽  
Naveed Ullah ◽  
Asim Ahmad Riaz ◽  
Muhammad Zeeshan Zahir ◽  
Zuhaib Ali Khan ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Mechanical Stability ◽  
Electrochemical Etching ◽  
Research Work ◽  
Cone Angle ◽  
Quartz Tuning Fork ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
High Quality ◽  
Scanning Electron

Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).

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

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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