Results 151 to 160 of about 909 (177)
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Optimized DFB laser diodes for a Butterfly QEPAS Sensor
OSA Optical Sensors and Sensing Congress 2021 (AIS, FTS, HISE, SENSORS, ES), 2021Optimized DFB lasers are presented. Results for the performance and its suitability for detecting trace gases are shown. We present our new QEPAS compact detection unit where everything is integrated into 14-pin butterfly housing.
Tobias Milde +6 more
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Compact portable QEPAS multi-gas sensor
SPIE Proceedings, 2011A quartz-enhanced photoacoustic spectroscopy (QEPAS) based multi-gas sensor was developed to quantify concentrations of carbon monoxide (CO), hydrogen cyanide (HCN), hydrogen chloride (HCl), and carbon dioxide (CO2) in ambient air. The sensor consists of a compact package of dimensions 25cm x 25cm x 10cm and was designed to operate at atmospheric ...
Lei Dong +3 more
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A QEPAS sensor with a ~1.37 μm DFB laser
Asia Communications and Photonics Conference 2013, 2013We demonstrate a QEPAS sensor using a ~1.37μm DFB laser as light source and a quartz tuning fork as a transducer to detect water vapor concentration in the air.
Ping Gong +3 more
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Numerical modeling and performance optimization of QEPAS spectrophone
SPIE Proceedings, 2012The spectrophone performance for QEPAS is numerically investigated by using a finite element method. The effect of varying system parameters such as the excitation frequency, relative position between the acoustic resonant tubes and the quartz tuning fork, and the dimensions of resonant tubes are examined A pair of rigid tubes, each with a length of ...
Yingchun Cao, Wei Jin, Hoi Lut Ho
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QEPAS methane sensor performance for humidified gases
Applied Physics B, 2008A trace gas sensor based on quartz enhanced photoacoustic spectroscopy (QEPAS) was evaluated using humidified nitrogen samples and ambient air. Relaxation processes following vibrational excitation of 2ν3 state of CH4 were investigated. Sensor performance at different gas pressures could be predicted based on a developed kinetic model.
A.A. Kosterev +4 more
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GaSb Diode Lasers for QEPAS Sensor Applications
Conference on Lasers and Electro-Optics, 2018Newly developed tunable single mode laser diodes based on GaSb material system in the wavelength range 1.6 μm ≤ λ ≤ 4 μm are combined with the QEPAS technique for trace gas detection.
Tobias Milde +4 more
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A new Method to Determine the Resonance Frequency in QEPAS
Conference on Lasers and Electro-Optics, 2018We present a novel method to determine the resonance frequency and Q factor of a quartz tuning fork (QTF) in quartz-enhanced photoacoustic spectroscopy (QEPAS) in a few seconds. A CHIRP modulates a laser diode.
Philipp Breitegger +2 more
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NIR diode laser-based QEPAS for acetylene detection
SPIE Proceedings, 2012Quartz-enhanced photoacoustic spectroscopy with a near infrared distributed feedback diode laser at 1.53 μm is demonstrated for acetylene detection at atmospheric pressure and room temperature. The P(9) absorption line in the ν1+ν3 band of C2H2 is selected for light absorption and photoacoustic pressure wave excitation.
Yingchun Cao, Wei Jin, Hoi Lut Ho
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Remote, distributed gas sensor based on FEW-QEPAS
Conference on Lasers and Electro-Optics, 2018A remote, distributed gas sensing using fiber evanescent wave quartz-enhanced photoacoustic spectroscopy (FEW-QEPAS) technique was demonstrated. A 3 km single mode fiber with multiple tapers was employed to perform long distance, distributed gas measurements.
Ying He +4 more
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QEPAS for chemical analysis of multi-component gas mixtures
Applied Physics B, 2010A gas sensor based on quartz-enhanced photoacoustic spectroscopy and using near-infrared, fiber-coupled diode lasers as an excitation source was developed for chemical analysis of gas mixtures containing H2S, CO2, and CH4 at concentrations from 0 to 100%. Analysis of physical phenomena affecting the sensor operation is performed, the sensor performance
A. A. Kosterev +4 more
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