scholarly journals Photoacoustic Measurement of Ethane with Near-Infrared DFB Diode Laser

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Gang Cheng ◽  
Yuan Cao ◽  
Kun Liu ◽  
Gongdong Zhu ◽  
Guishi Wang ◽  
...  
Keyword(s):  
Diode Laser ◽  
Near Infrared ◽  
Second Harmonic ◽  
Modulation Frequency ◽  
Photoacoustic Signal ◽  
Minimum Detectable Concentration ◽  
Modulation Amplitude ◽  
Excitation Light ◽  
Detection Scheme ◽  
Detectable Concentration

A compact resonant photoacoustic sensor based on a near-infrared distributed-feedback (DFB) diode laser was developed for detection of ethane (C2H6). A DFB laser emission at 5937.25 cm−1 with a power of ∼5 mW was used as an excitation light source for generating the photoacoustic signal. Wavelength modulation and second harmonic detection scheme were employed. Modulation frequency and modulation amplitude were optimized for getting optimum performance. Performance evaluation based on the linearity response of the PAS sensor system with respect to C2H6 concentration levels was performed, and a good linear dependence of the PAS signal on the C2H6 concentration was obtained. A minimum detectable concentration of 9 ppmv was achieved for detection of C2H6 with a lock-in time constant of 10 ms.

scholarly journals A simulation process of tunable open path diode laser spectrometer to detect a carbon monoxide gas in NIR region

2022 ◽  
Vol 961 (1) ◽  
pp. 012081
Author(s):  
Ruaa Kahtan Mahmood ◽  
Samira Adnan Mehdi
Keyword(s):  
Carbon Monoxide ◽  
Diode Laser ◽  
Near Infrared ◽  
Second Harmonic ◽  
Wave Length ◽  
Tunable Diode Laser ◽  
Theoretical Research ◽  
Laser Spectrometer ◽  
Diode Laser Spectrometer ◽  
Open Path

Abstract By modifying the wavelength of the open path tunable diode laser spectrometer (TDLS) in the near infrared region, theoretical research was implemented to improve the detection limit of carbon monoxide gas. To adjust the correct wavelength in the NIR area, MatLab code was created. Following that, frequency domain measurements were performed in order to extract the second harmonic as an indicator of gas presence. According to the results, the correct wave length in the NIR area is (1584.877 nm), and the lowest limit of CO gas concentration is (0.012 ppb).

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

1984 ◽  
Vol 39 (12) ◽  
pp. 1242-1249 ◽  
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.

Near-Infrared Diode Laser Based Spectroscopic Detection of Ammonia: A Comparative Study of Photoacoustic and Direct Optical Absorption Methods

2002 ◽  
Vol 56 (6) ◽  
pp. 715-719 ◽  
Author(s):  
Zoltán Bozóki ◽  
Árpád Mohácsi ◽  
Gábor Szabó ◽  
Zsolt Bor ◽  
Miklós Erdélyi ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Room Temperature ◽  
Near Infrared ◽  
Continuous Wave ◽  
Fast Response ◽  
Minimum Detectable Concentration ◽  
Mode Of Operation ◽  
Detectable Concentration ◽  
Ammonia Detection ◽  
Ppm Level

A photoacoustic spectroscopic (PAS) and a direct optical absorption spectroscopic (OAS) gas sensor, both using continuous-wave room-temperature diode lasers operating at 1531.8 nm, were compared on the basis of ammonia detection. Excellent linear correlation between the detector signals of the two systems was found. Although the physical properties and the mode of operation of both sensors were significantly different, their performances were found to be remarkably similar, with a sub-ppm level minimum detectable concentration of ammonia and a fast response time in the range of a few minutes.

Influence of CO2 Kinetic Cooling Effect on the Phase of Second Harmonic Gas Photoacoustic Signal

2013 ◽  
Vol 662 ◽  
pp. 532-536
Author(s):  
Zhi Ying Wu ◽  
Ming Lu ◽  
Qing Xu Yu
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Second Harmonic ◽  
Photoacoustic Signal ◽  
Cooling Effect ◽  
Transfer Model ◽  
Mixed Gas ◽  
Infrared Band ◽  
Co2 Gas ◽  
The Impact

Due to the impact of the CO2 kinetic cooling effect, which is kind of energy transfer between CO2 and N2 molecules, the mixed gas containing CO2, the amplitude of the photoacoustic signal and the detected gas concentration are no longer a linear change, and the signal phase also has been changed. In this study, the energy transfer model between CO2 and N2 molecules in near-infrared band (1～2.2μ) was derived, the influence from CO2 gas with different concentration on photoacoustic signal was discussed, and the relevant experimental tests were made，which showed that the proposed model can scientifically interpret the energy transfer relation between CO2 and N2 molecules and can quantitatively determine the influence from CO2 gas with different concentration on photoacoustic signals excited by mixed gas with including CO2 gas.

scholarly journals Cavity-enhanced photoacoustic sensor based on a whispering-gallery-mode diode laser

2019 ◽  
Author(s):  
Yufeng Pan ◽  
Lei Dong ◽  
Hongpeng Wu ◽  
Weiguang Ma ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Diode Laser ◽  
Signal Amplitude ◽  
Photoacoustic Signal ◽  
Whispering Gallery Mode ◽  
Gain Factor ◽  
Detection Sensitivity ◽  
Light Power ◽  
Excitation Light ◽  
Whispering Gallery ◽  
Averaging Time

Abstract. A cavity-enhanced photoacoustic (CEPA) sensor was developed based on an ultra-narrow linewidth whispering-gallery-mode (WGM) diode laser. A cavity-enhanced photoacoustic module (CEPAM) was designed to match the output beam from WGM-diode laser, resulting in an increase of the excitation light power, which, in turn, significantly enhanced the photoacoustic signal amplitude. The results show that a signal gain factor of 166 was achieved, which is in excellent agreement with the power enhancement factor of 175 after considering the power transmissivity. The performance of the sensor was evaluated in terms of the detection sensitivity and linearity. A 1σ detection limit of 0.45 ppmV for C2H2 detection was obtained at atmospheric pressure with a 1-s averaging time.

scholarly journals Cavity-enhanced photoacoustic sensor based on a whispering-gallery-mode diode laser

2019 ◽  
Vol 12 (3) ◽  
pp. 1905-1911 ◽  
Author(s):  
Yufeng Pan ◽  
Lei Dong ◽  
Hongpeng Wu ◽  
Weiguang Ma ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Diode Laser ◽  
Signal Amplitude ◽  
Photoacoustic Signal ◽  
Whispering Gallery Mode ◽  
Gain Factor ◽  
Detection Sensitivity ◽  
Light Power ◽  
Excitation Light ◽  
Whispering Gallery ◽  
Averaging Time

Abstract. A cavity-enhanced photoacoustic (CEPA) sensor was developed based on an ultra-narrow linewidth whispering-gallery-mode (WGM) diode laser. A cavity-enhanced photoacoustic module (CEPAM) was designed to match the output beam from the WGM-diode laser, resulting in an increase in the excitation light power, which, in turn, significantly enhanced the photoacoustic signal amplitude. The results show that a signal gain factor of 166 was achieved, which is in excellent agreement with the power enhancement factor of 175 after considering the power transmissivity. The performance of the sensor was evaluated in terms of the detection sensitivity and linearity. A 1σ detection limit of 0.45 ppmV for C2H2 detection was obtained at atmospheric pressure with a 1 s averaging time.

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