Simultaneous detection of methane, oxygen and water vapour utilising near-infrared diode lasers in conjunction with difference-frequency generation

Gustafsson, Ulf; Sandsten, Jonas; Svanberg, Sune

doi:10.1007/s003400000431

Cited by 23 publications

(6 citation statements)

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“…Moreover, in environmental safety, extreme demands are placed on the detection of the potential greenhouse gas methane [ 3 , 4 ]. Recently, various methane sensors have been developed on the basis of catalytic combustion [ 5 , 6 , 7 ], metal oxide semiconductor (MOX) [ 8 , 9 ], infrared spectrum [ 10 , 11 ], gas chromatography [ 12 , 13 ], and optical fiber [ 14 , 15 ]. Su et al reported that the catalytic combustion MEMS (microelectro-mechanical systems) sensors can detect 4000 ppm methane [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Coupling p+n Field-Effect Transistor Circuits for Low Concentration Methane Gas Detection

Zhou

Yang

Bian

et al. 2018

Sensors

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Nowadays, the detection of low concentration combustible methane gas has attracted great concern. In this paper, a coupling p+n field effect transistor (FET) amplification circuit is designed to detect methane gas. By optimizing the load resistance (RL), the response to methane of the commercial MP-4 sensor can be magnified ~15 times using this coupling circuit. At the same time, it decreases the limit of detection (LOD) from several hundred ppm to ~10 ppm methane, with the apparent response of 7.0 ± 0.2 and voltage signal of 1.1 ± 0.1 V. This is promising for the detection of trace concentrations of methane gas to avoid an accidental explosion because its lower explosion limit (LEL) is ~5%. The mechanism of this coupling circuit is that the n-type FET firstly generates an output voltage (VOUT) amplification process caused by the gate voltage-induced resistance change of the FET. Then, the p-type FET continues to amplify the signal based on the previous VOUT amplification process.

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Section: Introductionmentioning

confidence: 99%

Coupling p+n Field-Effect Transistor Circuits for Low Concentration Methane Gas Detection

Zhou

Yang

Bian

et al. 2018

Sensors

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“…An example of the for-0003-6935/08/122028-07$15.00/0 © 2008 Optical Society of America mer is given in [6], where water vapor, nitrogen dioxide, and sulfur dioxide can be measured using two diode lasers. The latter is illustrated in [7], where molecular oxygen, water vapor, and methane can be studied. However, the drawback of these techniques is the low light intensity of the generated frequency (normally a factor of ∼1000 lower than the intensity of the light sources).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous detection of molecular oxygen and water vapor in the tissue optical window using tunable diode laser spectroscopy

et al. 2008

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Simultaneous detection of molecular oxygen and water vapor in the tissue optical window using tunable diode laser spectroscopy Persson, Linda; Andersson, Mats; Lewander, Märta; Svanberg, Katarina; Svanberg, Sune General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Simultaneous detection of molecular oxygen and water vapor in the tissue optical window using tunable diode laser spectroscopy We report on a dual-diode laser spectroscopic system for simultaneous detection of two gases. The technique is demonstrated by performing gas measurements on absorbing samples such as an air distance, and on absorbing and scattering porous samples such as human tissue. In the latter it is possible to derive the concentration of one gas by normalizing to a second gas of known concentration. This is possible if the scattering and absorption of the bulk material is equal or similar for the two wavelengths used, resulting in a common effective pathlength. Two pigtailed diode lasers are operated in a wavelength modulation scheme to detect molecular oxygen ∼760 nm and water vapor ∼935 nm within the tissue optical window (600 nm to 1:3 μm). Different modulation frequencies are used to distinguish between the two wavelengths. No crosstalk can be observed between the gas contents measured in the two gas channels. The system is made compact by using a computer board and performing software-based lock-in detection.The noise floor obtained corresponds to an absorption fraction of approximately 6 × 10 À5 for both oxygen and water vapor, yielding a minimum detection limit of ∼2 mm for both gases in ambient air. The power of the technique is illustrated by the preliminary results of a clinical trial, nonintrusively investigating gas in human sinuses.

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“…With high enough midinfrared power for nearly shot-noise-limited detection (~0.1 mW depending on the detector), a normalized noiseequivalent absorption coefficient (NNEA * ) as small as 10 -6 to 10 -8 cm -1 Hz -1/2 can be obtained, especially if balanced detection etc. is used to compensate for the noise caused by power fluctuations of the light source [151,152,153,154]. When used for spectroscopy of strong fundamental vibrational transitions of molecules like CH 4 and N 2 O within the atmospheric window between 3 and 5 µm (Fig.…”

Section: Trace Gas Detectionmentioning

confidence: 99%

“…is used to compensate for the noise caused by power fluctuations of the light source. [151][152][153][154] When used for spectroscopy of strong fundamental vibrational transitions of molecules like CH 4 and N 2 O within the atmospheric window between 3 and 5 mm (Fig. 1), this translates into a detection limit of B1 ppm (parts-per-million) volume-mixing ratio with a typical absorption path length of 1 m. An obvious solution to improve the sensitivity of trace gas detection is to increase the absorption path length.…”

Section: Trace Gas Detectionmentioning

confidence: 99%

Mid-infrared optical parametric oscillators and frequency combs for molecular spectroscopy

Vainio

Halonen

2016

Phys. Chem. Chem. Phys.

131

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Nonlinear optical frequency conversion is one of the most versatile methods to generate wavelength-tunable laser light in the mid-infrared region. This spectral region is particularly important for trace gas detection and other applications of molecular spectroscopy, because it accommodates the fundamental vibrational bands of several interesting molecules. In this article, we review the progress of the most significant nonlinear optics instruments for widely tunable, high-resolution mid-infrared spectroscopy: continuous-wave optical parametric oscillators and difference frequency generators. We extend our discussion to mid-infrared optical frequency combs, which are becoming increasingly important spectroscopic tools, owing to their capability of highly sensitive and selective parallel detection of several molecular species. To illustrate the potential and limitations of mid-infrared sources based on nonlinear optics, we also review typical uses of these instruments in both applied and fundamental spectroscopy.

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Simultaneous detection of methane, oxygen and water vapour utilising near-infrared diode lasers in conjunction with difference-frequency generation

Cited by 23 publications

References 0 publications

Coupling p+n Field-Effect Transistor Circuits for Low Concentration Methane Gas Detection

Coupling p+n Field-Effect Transistor Circuits for Low Concentration Methane Gas Detection

Simultaneous detection of molecular oxygen and water vapor in the tissue optical window using tunable diode laser spectroscopy

Mid-infrared optical parametric oscillators and frequency combs for molecular spectroscopy

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