Photoacoustic gas sensing with a commercial external cavity-quantum cascade laser at 10.5μm

Mammez, Dominique; Stoeffler, Clara; Cousin, Julien; Vallon, R.; Mammez, Marie-Hélène; Joly, Lilian; Parvitte, B.; Zéninari, V.

doi:10.1016/j.infrared.2013.07.002

Cited by 12 publications

(5 citation statements)

References 16 publications

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“…The QCL output wavelength can be tuned by adjusting the external cavity that is controlled by an optical encoder, either by stepwise or continuous tuning. It has been shown that continuously scanning the spectra generally provided better signal-to-noise (S/N) ratio and higher resolution 34,35 as mechanical adjustment of the external cavity has drift between different scan cycles. 10 This is especially important for stand-off spectroscopy with a long optical path and complicated air absorption peaks in the baseline.…”

Section: Experimental Methodsmentioning

confidence: 99%

Broadband Mid-Infrared Stand-Off Reflection–Absorption Spectroscopy Using a Pulsed External Cavity Quantum Cascade Laser

et al. 2017

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Broadband mid-infrared molecular spectroscopy is essential for detection and identification of many chemicals and materials. In this report, we present stand-off mid-infrared spectra of 1,3,5-trinitro-1,3,5-triazine or cyclotrimethylene trinitramine (RDX) residues on a stainless-steel surface measured by a broadband external cavity quantum cascade laser (QCL) system. The pulsed QCL is continuously scanned over 800 cm in the molecular fingerprint region and the amplitude of the reflection signal is measured by either a boxcar-averager-based scheme or a lock-in-amplifier-based scheme with 1 MHz and 100 kHz quartz crystal oscillators. The main background noise is due to the laser source instability and is around 0.1% of normalized intensity. The direct absorption spectra have linewidth resolution around 0.1 cm and peak height sensitivity around 10 due to baseline interference fringes. Stand-off detection of 5-50 µg/cm of RDX trace adsorbed on a stainless steel surface at the distance of 5 m is presented.

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Section: Experimental Methodsmentioning

confidence: 99%

Broadband Mid-Infrared Stand-Off Reflection–Absorption Spectroscopy Using a Pulsed External Cavity Quantum Cascade Laser

et al. 2017

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“…In GSMA, the implementation of a commercial EC QCL emitting at 10.5 μm in a photoacoustic spectrometer was realized and enables measurements on broad spectral range up to 60 cm −1 . The tuning range of the source emitting from 10 µm to 10.5 µm demonstrates the possibility to detect small and complex molecules such as carbon dioxide (CO 2 ) and butane (C 4 H 10 ) [ 52 ]. Based on the same principle, an EC QCL spectrometer was designed in the lab at 7.5 μm.…”

Section: External-cavity Quantum Cascade Laser (Ec Qcl)mentioning

confidence: 99%

“…This technique has been demonstrated at room temperature [ 49 ] with high-power [ 50 ] for high resolution spectroscopy and chemical sensing [ 51 ]. In GSMA, the implementation of a commercial EC QCL emitting at 10.5 μm in a photoacoustic spectrometer was realized [ 52 ] and enabled measurements on a broad spectral range up to 60 cm −1 . The tuning range of the source emitting from 10 µm to 10.5 µm demonstrates the possibility to detect small and complex molecules such as carbon dioxide (CO 2 ) and butane (C 4 H 10 ).…”

Section: Introductionmentioning

confidence: 99%

Widely-Tunable Quantum Cascade-Based Sources for the Development of Optical Gas Sensors

Zéninari

Vallon

Bizet

et al. 2020

Sensors

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Spectroscopic techniques based on Distributed FeedBack (DFB) Quantum Cascade Lasers (QCL) provide good results for gas detection in the mid-infrared region in terms of sensibility and selectivity. The main limitation is the QCL relatively low tuning range (~10 cm−1) that prevents from monitoring complex species with broad absorption spectra in the infrared region or performing multi-gas sensing. To obtain a wider tuning range, the first solution presented in this paper consists of the use of a DFB QCL array. Tuning ranges from 1335 to 1387 cm−1 and from 2190 to 2220 cm−1 have been demonstrated. A more common technique that will be presented in a second part is to implement a Fabry–Perot QCL chip in an external-cavity (EC) system so that the laser could be tuned on its whole gain curve. The use of an EC system also allows to perform Intra-Cavity Laser Absorption Spectroscopy, where the gas sample is placed within the laser resonator. Moreover, a technique only using the QCL compliance voltage technique can be used to retrieve the spectrum of the gas inside the cavity, thus no detector outside the cavity is needed. Finally, a specific scheme using an EC coherent QCL array can be developed. All these widely-tunable Quantum Cascade-based sources can be used to demonstrate the development of optical gas sensors.

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“…This instrument was originally dedicated to the methane detection with near-infrared diode lasers, then Quantum Cascade Lasers (QCL) appeared as a new opportunity for improvements in gas detection as the PA response is linear with power [3]. More recently the sensor was implemented with a commercial external cavity-QCL emitting at 10.5 μm and allowed the possibility to detect small and complex molecules such as carbon dioxide and butane [4]. For these works, the geometry of the Helmholtz cell was not modified but improvements in the microphone sensitivity and the laser specifications allow decreasing the detection limit down to the ppb level.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Finite Element Modelling of Compact Photoacoustic Gas Sensors

2020

Journal of Materials Sciences and Applications

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We report on the demonstration of quantitative simulation of compact photoacoustic cells signals. The finite element method is used to calculate the response of differential Helmholtz resonator cells of two different sizes. Simulated quality factors and resonance frequencies are compared with experimental ones. Taking account of the gas sample absorption coefficient and the laser intensity, cell constants are also evaluated and compared to experimental values showing a very good agreement. For compact sensors, where sub-millimeter features are present, the resolution of the pressure acoustics equation is not sufficient to reproduce experimental results and a viscothermal model must be used.

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Photoacoustic gas sensing with a commercial external cavity-quantum cascade laser at 10.5μm

Cited by 12 publications

References 16 publications

Broadband Mid-Infrared Stand-Off Reflection–Absorption Spectroscopy Using a Pulsed External Cavity Quantum Cascade Laser

Broadband Mid-Infrared Stand-Off Reflection–Absorption Spectroscopy Using a Pulsed External Cavity Quantum Cascade Laser

Widely-Tunable Quantum Cascade-Based Sources for the Development of Optical Gas Sensors

Quantitative Finite Element Modelling of Compact Photoacoustic Gas Sensors

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