scholarly journals Tailored Algorithm for Sensitivity Enhancement of Gas Concentration Sensors Based on Tunable Laser Absorption Spectroscopy

Sensors ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 1808
Author(s):  
Everardo Vargas-Rodriguez ◽  
Ana Guzman-Chavez ◽  
Roberto Baeza-Serrato
Keyword(s):  
Absorption Spectroscopy ◽  
Tunable Laser ◽  
Sensitivity Enhancement ◽  
Laser Absorption Spectroscopy ◽  
Gas Concentration ◽  
Laser Absorption

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.

scholarly journals Measurement of Atmospheric Dimethyl Sulfide with a Distributed Feedback Interband Cascade Laser

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3216 ◽  
Author(s):  
Shuanke Wang ◽  
Zhenhui Du ◽  
Liming Yuan ◽  
Yiwen Ma ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Dimethyl Sulfide ◽  
Tunable Laser ◽  
Distributed Feedback ◽  
Integration Time ◽  
Laser Absorption Spectroscopy ◽  
Atmospheric Measurements ◽  
Pure Nitrogen ◽  
Laser Absorption ◽  
Interband Cascade Laser

This paper presents a mid-infrared dimethyl sulfide (CH3SCH3, DMS) sensor based on tunable laser absorption spectroscopy with a distributed feedback interband cascade laser to measure DMS in the atmosphere. Different from previous work, in which only DMS was tested and under pure nitrogen conditions, we measured DMS mixed by common air to establish the actual atmospheric measurement environment. Moreover, we used tunable laser absorption spectroscopy with spectral fitting to enable multi-species (i.e., DMS, CH4, and H2O) measurement simultaneously. Meanwhile, we used empirical mode decomposition and greatly reduced the interference of optical fringes and noise. The sensor performances were evaluated with atmospheric mixture in laboratory conditions. The sensor’s measurement uncertainties of DMS, CH4, and H2O were as low as 80 ppb, 20 ppb, and 0.01% with an integration time 1 s, respectively. The sensor possessed a very low detection limit of 9.6 ppb with an integration time of 164 s for DMS, corresponding to an absorbance of 7.4 × 10−6, which showed a good anti-interference ability and stable performance after optical interference removal. We demonstrated that the sensor can be used for DMS measurement, as well as multi-species atmospheric measurements of DMS, H2O, and CH4 simultaneously.

DFB interband cascade lasers for tunable laser absorption spectroscopy from 3 to 6 μm

2013 ◽  
Author(s):  
M. von Edlinger ◽  
J. Scheuermann ◽  
L. Nähle ◽  
C. Zimmermann ◽  
L. Hildebrandt ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Tunable Laser ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Interband Cascade Lasers ◽  
Cascade Lasers
Sign in / Sign up

Export Citation Format

Share Document