Application of Difference Frequency Laser in Trace Gas Measurement System

2011 ◽  
Vol 225-226 ◽  
pp. 1323-1326
Author(s):  
Qiu Xia Yang ◽  
Yang Ping Zhu ◽  
Zhi Quan Li ◽  
Zheng Jun Liu
Keyword(s):  
Frequency Conversion ◽  
Nonlinear Crystal ◽  
Far Infrared ◽  
Measurement Model ◽  
Concentration Measurement ◽  
Tunable Diode Laser ◽  
Difference Frequency ◽  
Trace Gas ◽  
Laser Source ◽  
Gas Concentration

Based on Nd:YAG laser, tunable diode laser, electro-optic amplitude modulator and the difference frequency generator, a servo scanning laser source is designed, and the principle of trace gas concentration measurement model is introduced as well, which can realize the gas concentration measurement in the band of mid-infrared and far-infrared. Based on the theory of electromagnetic field, mutual coupling equation about laser transmission in nonlinear crystal and the optical frequency conversion characteristics are analyzed theoretically. As a result, in the range of far-field, electric field intensity of coupled wave increases approximatively exponentially,then tends to be stable.

Development of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection

2002 ◽  
Vol 75 (2-3) ◽  
pp. 281-288 ◽  
Author(s):  
D. Richter ◽  
A. Fried ◽  
B.P. Wert ◽  
J.G. Walega ◽  
F.K. Tittel
Keyword(s):  
Difference Frequency ◽  
Gas Detection ◽  
Trace Gas ◽  
Laser Source ◽  
Trace Gas Detection ◽  
Highly Sensitive ◽  
Frequency Laser

scholarly journals TDLAS Monitoring of Carbon Dioxide with Temperature Compensation in Power Plant Exhausts

2019 ◽  
Vol 9 (3) ◽  
pp. 442 ◽  
Author(s):  
Xiaorui Zhu ◽  
Shunchun Yao ◽  
Wei Ren ◽  
Zhimin Lu ◽  
Zhenghui Li
Keyword(s):  
Carbon Dioxide ◽  
Power Plant ◽  
Diode Laser ◽  
Flue Gas ◽  
Temperature Compensation ◽  
Concentration Measurement ◽  
Tunable Diode Laser ◽  
Laser Source ◽  
Compensation Methods ◽  
Relative Standard

Temperature variations of flue gas have an effect on carbon dioxide (CO2) emissions monitoring. This paper demonstrates accurate CO2 concentration measurement using tunable diode laser absorption spectroscopy (TDLAS) with temperature compensation methods. A distributed feedback diode laser at 1579 nm was chosen as the laser source for CO2 measurements. A modeled flue gas was made referring to CO2 concentrations of 10–20% and temperatures of 298–338 K in the exhaust of a power plant. Two temperature compensation methods based on direct absorption (DA) and wavelength modulation (WMS) are presented to improve the accuracy of the concentration measurement. The relative standard deviations of DA and WMS measurements of concentration were reduced from 0.84% and 0.35% to 0.42% and 0.31%, respectively. Our experimental results have validated the rationality of temperature compensations and can be further applied for high-precision measurement of gas concentrations in industrial emission monitoring.

Efficient cascaded difference frequency conversion in periodically poled Ti:LiNbO3 waveguides using pulsed and cw pumping

2001 ◽  
Vol 73 (5-6) ◽  
pp. 501-504 ◽  
Author(s):  
G. Schreiber ◽  
H. Suche ◽  
Y.L. Lee ◽  
W. Grundkötter ◽  
V. Quiring ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Difference Frequency ◽  
Periodically Poled

A Fire Warning Method Using Tunable Diode Laser Absorption Spectroscopy

2021 ◽  
Vol 16 (2) ◽  
pp. 222-229
Author(s):  
Lin Feng ◽  
Jian Wang ◽  
Chao Ding
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Gas Absorption ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Gas Concentration ◽  
Laser Absorption ◽  
Output Wavelength ◽  
Light Beams ◽  
Diode Laser Absorption

Tunable diode laser absorption spectroscopy (TDLAS) technology is adopted herein to detect fire gas produced in the early stage of the fire. Based on this technology, a fire warning detection system with multiple lasers and detectors is proposed. Multiple drivers input laser’s temperature and injected current data, making its output wavelength consistent with the measured gas’ absorption peak wavelengths in absorption spectroscopy. Multiple light beams are coupled to the same optical fiber. After the light beams pass through the long optical path absorption cell filled with fire gas, the beams are separated by a converter. The signals are demodulated by different detectors and further analyzed for fire warnings. After the fire warning system’s design, the system’s various hardware modules are designed, including the light source module, TDLAS controller, gas chamber module, photoelectric detector, and data collection. When the temperature remains unchanged, the output wavelength is linearly related to the injected current. When the injected current remains unchanged, the output wavelength is linearly related to the operating temperature. With a semiconductor laser’s injected current of 40 mA, the initial temperature of 38.6 °C, and the output wavelength of 1578.16 nm, the output wavelength increases continuously as the temperature increases. The harmonic signal amplitude after gas absorption is positively correlated with the measured gas concentration, indicating that the second harmonic signals can estimate the fire gas concentration.

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