scholarly journals Dual-Gas Sensor of CH4/C2H6 Based on Wavelength Modulation Spectroscopy Coupled to a Home-Made Compact Dense-Pattern Multipass Cell

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 820 ◽  
Author(s):  
Xing Tian ◽  
Yuan Cao ◽  
Jiajin Chen ◽  
Kun Liu ◽  
Guishi Wang ◽  
...  
Keyword(s):  
Semiconductor Lasers ◽  
Gas Sensor ◽  
Second Harmonic ◽  
Simultaneous Detection ◽  
Multipass Cell ◽  
Wavelength Modulation ◽  
Harmonic Detection ◽  
Modulation Spectroscopy ◽  
Averaging Time ◽  
Dense Pattern

A sensitive dual-gas sensor for the detection of CH4 and C2H6 is demonstrated. Two tunable semiconductor lasers operating at 1.653 μm (for CH4 monitoring) and 1.684 μm (for C2H6) were used as the light source for spectroscopic measurements of CH4 and C2H6. Long-path absorption in a home-made compact dense-pattern multipass cell (Leff = 29.37 m) was employed, combined with wavelength modulation and second harmonic detection. Simultaneous detection of CH4 and C2H6 was achieved by separated wavelength modulations of the two lasers. Modulation frequencies and amplitudes were optimized for sensitivity detection of CH4 and C2H6 simultaneously. The dual-gas sensor exhibits 1σ detection limits of 1.5 ppbv for CH4 in 140 s averaging time and 100 ppbv for C2H6 in 200 s.

Mid-infrared ChG-on-MgF2 waveguide gas sensor based on wavelength modulation spectroscopy

2021 ◽  
Author(s):  
Mingquan Pi ◽  
Chuantao Zheng ◽  
Huan Zhao ◽  
Zihang Peng ◽  
Jiaming Lang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Wavelength Modulation Spectroscopy ◽  
Wavelength Modulation ◽  
Mid Infrared ◽  
Modulation Spectroscopy

scholarly journals Compact Open-Path Sensor for Fast Measurements of CO2 and H2O using Scanned-Wavelength Modulation Spectroscopy with 1f-Phase Method

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1910
Author(s):  
Xiang Li ◽  
Feng Yuan ◽  
Mai Hu ◽  
Bin Chen ◽  
Yabai He ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Fast Response ◽  
Wavelength Modulation Spectroscopy ◽  
Phase Method ◽  
High Temporal Resolution ◽  
Wavelength Modulation ◽  
Modulation Spectroscopy ◽  
Open Path ◽  
Averaging Time ◽  
Term Performance

We report here the development of a compact, open-path CO2 and H2O sensor based on the newly introduced scanned-wavelength modulation spectroscopy with the first harmonic phase angle (scanned-WMS-θ1f) method for high-sensitivity, high temporal resolution, ground-based measurements. The considerable advantage of the sensor, compared with existing commercial ones, lies in its fast response of 500 Hz that makes this instrument ideal for resolving details of high-frequency turbulent motion in exceptionally dynamic coastal regions. The good agreement with a commercial nondispersive infrared analyzer supports the utility and accuracy of the sensor. Allan variance analysis shows that the concentration measurement sensitivities can reach 62 ppb CO2 in 0.06 s and 0.89 ppm H2O vapor in 0.26 s averaging time. Autonomous field operation for 15-day continuous measurements of greenhouse gases (CO2/H2O) was performed on a shore-based monitoring tower in Daya Bay, demonstrating the sensor’s long-term performance. The capability for high-quality fast turbulent atmospheric gas observations allow the potential for better characterization of oceanographic processes.

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