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Optical Gas Sensing: Media, Mechanisms and Applications

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Keywords
Published Papers

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Optical Sensors".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 33605

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Special Issue Editors

Prof. Dr. Krzysztof M. Abramski

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Guest Editor

Laser & Fiber Electronis Group, Faculty of Electronics, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
Interests: laser spectroscopy; laser gas sensing; laser frequency stabilization; gas lasers; slab and multichannel CO2 RF excited lasers; microchip solid-state single-frequency lasers; laser vibrometry; laser heterodyning; optical fiber combs; mode-locking; femtosecond fiber lasers; phase-locking of laser beams

Dr. Piotr Jaworski

E-Mail Website
Guest Editor

Laser Spectroscopy Group, Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
Interests: laser-based spectroscopy; laser-based gas sensing; microstructured optical fibers; hollow-core photonic crystal fibers; fiber lasers
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Optical gas sensing is one of the fastest developing research areas of laser spectroscopy. Continuous development of new coherent light sources operating in the Mid-IR and Far-IR regions (QCL - Quantum Cascade Lasers, ICL – Intraband Cascade Lasers , OPO – Optical Parametric Oscillator, DFG - Difference Frequency Generation, optical combs etc.) stimulate new sophisticated methods and technological solutions in this area. Development of clever techniques of gas detection based on new mechanisms of sensing (photoacoustic, photothermal, dispersion etc.) supported by advanced applied electronics and huge progress in signal processing allow to introduce more sensitive, more broadband and miniaturized optical sensors. Additionally, substantial advancement of fast and sensitive photodetectors in MIR and FIR supports very much gas sensing progress.

Recent material and technological progress in the development of hollow-core optical fibers allowing low-loss transmission in both NIR and MIR opens a new route for obtaining low volume long optical paths so strongly required in laser-based gas sensors. The first successful demonstrations of using hollow-core fibers as gas absorption cells have been already demonstrated. The next important subject in the area opening huge possibilities is based on frequency comb spectroscopy, with its recent mutation – dual-comb spectroscopy. Furthermore, recently introduced, the so called laser-intra-cavity heterodyne gas detection technique seems to make important progress in improving sensitivity and miniaturization of the sensors.

The aim of this Special Issue is to give some insight into trends in optical gas sensing, including new visions, new techniques, novel materials and devices.

Topics include, but are not limited to the following:

absorption spectroscopy
photoacoustic and photothermal spectroscopy
dispersion spectroscopy
frequency comb spectroscopy
heterodyne-based techniques
optical fibers
mid-infrared laser sources
remote sensing
application of laser based gas sensors

Prof. Dr. Krzysztof M. Abramski
Dr. Piotr Jaworski
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

absorption spectroscopy
photoacoustic spectroscopy
photothermal spectroscopy
heterodyne detection
dispersion spectroscopy
frequency comb spectroscopy
microsctructured optical fibers
hollow-core fibers
mid-infrared lasers
laser-based gas sensing
remote sensing
laser sources
gas sensing applications, signal processing

Published Papers (12 papers)

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Research

Jump to: Review

22 pages, 3669 KiB

Open AccessArticle

A Compact Fiber-Coupled NIR/MIR Laser Absorption Instrument for the Simultaneous Measurement of Gas-Phase Temperature and CO, CO₂, and H₂O Concentration

by Lin Shi, Torsten Endres, Jay B. Jeffries, Thomas Dreier and Christof Schulz

Sensors 2022, 22(3), 1286; https://0-doi-org.brum.beds.ac.uk/10.3390/s22031286 - 08 Feb 2022

Cited by 2 | Viewed by 2220

Abstract

A fiber-coupled, compact, remotely operated laser absorption instrument is developed for CO, CO₂, and H₂O measurements in reactive flows at the elevated temperatures and pressures expected in gas turbine combustor test rigs with target pressures from 1–25 bar and temperatures of up to 2000 K. The optical engineering for solutions of the significant challenges from the ambient acoustic noise (~120 dB) and ambient test rig temperatures (60 °C) are discussed in detail. The sensor delivers wavelength-multiplexed light in a single optical fiber from a set of solid-state lasers ranging from diodes in the near-infrared (~1300 nm) to quantum cascade lasers in the mid-infrared (~4900 nm). Wavelength-multiplexing systems using a single optical fiber have not previously spanned such a wide range of laser wavelengths. Gas temperature is inferred from the ratio of two water vapor transitions. Here, the design of the sensor, the optical engineering required for simultaneous fiber delivery of a wide range of laser wavelengths on a single optical line-of-sight, the engineering required for sensor survival in the harsh ambient environment, and laboratory testing of sensor performance in the exhaust gas of a flat flame burner are presented. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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Figure 1

12 pages, 1837 KiB

Open AccessArticle

Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors

by Simon Gassner, Rainer Schaller, Matthias Eberl, Carsten von Koblinski, Simon Essing, Mohammadamir Ghaderi, Katrin Schmitt and Jürgen Wöllenstein

Sensors 2022, 22(2), 685; https://0-doi-org.brum.beds.ac.uk/10.3390/s22020685 - 17 Jan 2022

Cited by 2 | Viewed by 2307

Abstract

We present a concept for a wafer-level manufactured photoacoustic transducer, suitable to be used in consumer-grade gas sensors. The transducer consists of an anodically bonded two-layer stack of a blank silicon wafer and an 11 µm membrane, which was wet-etched from a borosilicate wafer. The membrane separates two cavities; one of which was hermetically sealed and filled with CO₂ during the anodic bonding and acts as an infrared absorber. The second cavity was designed to be connected to a standard MEMS microphone on PCB-level forming an infrared-sensitive photoacoustic detector. CO₂ sensors consisting of the detector and a MEMS infrared emitter were built up and characterized towards their sensitivity and noise levels at six different component distance ranging from 3.0 mm to 15.5 mm. The signal response for the sample with the longest absorption path ranged from a decrease of 8.3% at a CO₂ concentration of 9400 ppm to a decrease of

0.8

% at a concentration of 560 ppm. A standard deviation of the measured values of 18 ppm was determined when the sensor was exposed to 1000 ppm CO₂. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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Figure 1

16 pages, 4733 KiB

Open AccessArticle

Fabrication of Microchannels in a Nodeless Antiresonant Hollow-Core Fiber Using Femtosecond Laser Pulses

by Paweł Kozioł, Piotr Jaworski, Karol Krzempek, Viktoria Hoppe, Grzegorz Dudzik, Fei Yu, Dakun Wu, Meisong Liao, Jonathan Knight and Krzysztof Abramski

Sensors 2021, 21(22), 7591; https://0-doi-org.brum.beds.ac.uk/10.3390/s21227591 - 16 Nov 2021

Cited by 7 | Viewed by 1990

Abstract

In this work, we present femtosecond laser cutting of microchannels in a nodeless antiresonant hollow-core fiber (ARHCF). Due to its ability to guide light in an air core combined with exceptional light-guiding properties, an ARHCF with a relatively non-complex structure has a high application potential for laser-based gas detection. To improve the gas flow into the fiber core, a series of 250 × 30 µm microchannels were reproducibly fabricated in the outer cladding of the ARHCF directly above the gap between the cladding capillaries using a femtosecond laser. The execution time of a single lateral cut for optimal process parameters was 7 min. It has been experimentally shown that the implementation of 25 microchannels introduces low transmission losses of 0.17 dB (<0.01 dB per single microchannel). The flexibility of the process in terms of the length of the performed microchannel was experimentally demonstrated, which confirms the usefulness of the proposed method. Furthermore, the performed experiments have indicated that the maximum bending radius for the ARHCF, with the processed 100 µm long microchannel that did not introduce its breaking, is 15 cm. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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19 pages, 26682 KiB

Open AccessArticle

The Short-Term Performances of Two Independent Gas Modulated Refractometers for Pressure Assessments

by Clayton Forssén, Isak Silander, Johan Zakrisson, Ove Axner and Martin Zelan

Sensors 2021, 21(18), 6272; https://0-doi-org.brum.beds.ac.uk/10.3390/s21186272 - 18 Sep 2021

Cited by 8 | Viewed by 1672

Abstract

Refractometry is a powerful technique for pressure assessments that, due to the recent redefinition of the SI system, also offers a new route to realizing the SI unit of pressure, the Pascal. Gas modulation refractometry (GAMOR) is a methodology that has demonstrated an [...] Read more.

10^{- 7}

region. However, its short-term performance, which is of importance for a variety of applications, has not yet been scrutinized. To assess this, we investigated the short-term performance (in terms of precision) of two similar, but independent, dual Fabry–Perot cavity refractometers utilizing the GAMOR methodology. Both systems assessed the same pressure produced by a dead weight piston gauge. That way, their short-term responses were assessed without being compromised by any pressure fluctuations produced by the piston gauge or the gas delivery system. We found that the two refractometer systems have a significantly higher degree of concordance (in the

10^{- 8}

range at 1 s) than what either of them has with the piston gauge. This shows that the refractometry systems under scrutiny are capable of assessing rapidly varying pressures (with bandwidths up to 2 Hz) with precision in the

10^{- 8}

range. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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Graphical abstract

12 pages, 2882 KiB

Open AccessArticle

Direct Comb Vernier Spectroscopy for Fractional Isotopic Ratio Determinations

by Mario Siciliani de Cumis, Roberto Eramo, Jie Jiang, Martin E. Fermann and Pablo Cancio Pastor

Sensors 2021, 21(17), 5883; https://0-doi-org.brum.beds.ac.uk/10.3390/s21175883 - 31 Aug 2021

Cited by 1 | Viewed by 1568

Abstract

Accurate isotopic composition analysis of the greenhouse-gasses emitted in the atmosphere is an important step to mitigate global climate warnings. Optical frequency comb–based spectroscopic techniques have shown ideal performance to accomplish the simultaneous monitoring of the different isotope substituted species of such gases. The capabilities of one such technique, namely, direct comb Vernier spectroscopy, to determine the fractional isotopic ratio composition are discussed. This technique combines interferometric filtering of the comb source in a Fabry–Perot that contains the sample gas, with a high resolution dispersion spectrometer to resolve the spectral content of each interacting frequency inside of the Fabry–Perot. Following this methodology, simultaneous spectra of ro-vibrational transitions of

^{12}

^{16}

_{2}

and

^{13}

^{16}

_{2}

molecules are recorded and analyzed with an accurate fitting procedure. Fractional isotopic ratio

^{13}

^{12}

C at 3% of precision is measured for a sample of CO

_{2}

gas, showing the potentialities of the technique for all isotopic-related applications of this important pollutant. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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Figure 1

10 pages, 2622 KiB

Open AccessArticle

Application of High-Speed Quantum Cascade Detectors for Mid-Infrared, Broadband, High-Resolution Spectroscopy

by Tatsuo Dougakiuchi and Naota Akikusa

Sensors 2021, 21(17), 5706; https://0-doi-org.brum.beds.ac.uk/10.3390/s21175706 - 24 Aug 2021

Cited by 5 | Viewed by 3072

Abstract

Broadband, high-resolution, heterodyne, mid-infrared absorption spectroscopy was performed with a high-speed quantum cascade (QC) detector. By strictly reducing the device capacitance and inductance via air-bridge wiring and a small mesa structure, a 3-dB frequency response over 20 GHz was obtained for the QC detector, which had a 4.6-μm peak wavelength response. In addition to the high-speed, it exhibited low noise characteristics limited only by Johnson–Nyquist noise, bias-free operation without cooling, and photoresponse linearity over a wide dynamic range. In the detector characterization, the noise-equivalent power was 7.7 × 10⁻¹¹ W/Hz^1/2 at 4.6 μm, and it had good photoresponse linearity up to 250 mW, with respect to the input light power. Broadband and high-accuracy molecular spectroscopy based on heterodyne detection was demonstrated by means of two distributed-feedback 4.5-μm QC lasers. Specifically, several nitrous oxide absorption lines were acquired over a wavelength range of 0.8 cm⁻¹ with the wide-band QC detector. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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13 pages, 5891 KiB

Open AccessCommunication

Development of a Laser Gas Analyzer for Fast CO₂ and H₂O Flux Measurements Utilizing Derivative Absorption Spectroscopy at a 100 Hz Data Rate

by Mingxing Li, Ruifeng Kan, Yabai He, Jianguo Liu, Zhenyu Xu, Bing Chen, Lu Yao, Jun Ruan, Huihui Xia, Hao Deng, Xueli Fan, Bangyi Tao and Xueling Cheng

Sensors 2021, 21(10), 3392; https://0-doi-org.brum.beds.ac.uk/10.3390/s21103392 - 13 May 2021

Cited by 5 | Viewed by 2723

Abstract

We report the development of a laser gas analyzer that measures gas concentrations at a data rate of 100 Hz. This fast data rate helps eddy covariance calculations for gas fluxes in turbulent high wind speed environments. The laser gas analyzer is based on derivative laser absorption spectroscopy and set for measurements of water vapor (H₂O, at wavelength ~1392 nm) and carbon dioxide (CO₂, at ~2004 nm). This instrument, in combination with an ultrasonic anemometer, has been tested experimentally in both marine and terrestrial environments. First, we compared the accuracy of results between the laser gas analyzer and a high-quality commercial instrument with a max data rate of 20 Hz. We then analyzed and compared the correlation of H₂O flux results at data rates of 100 Hz and 20 Hz in both high and low wind speeds to verify the contribution of high frequency components. The measurement results show that the contribution of 100 Hz data rate to flux calculations is about 11% compared to that measured with 20 Hz data rate, in an environment with wind speed of ~10 m/s. Therefore, it shows that the laser gas analyzer with high detection frequency is more suitable for measurements in high wind speed environments. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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14 pages, 1587 KiB

Open AccessArticle

Fast Quantification of Air Pollutants by Mid-Infrared Hyperspectral Imaging and Principal Component Analysis

by Juan Meléndez and Guillermo Guarnizo

Sensors 2021, 21(6), 2092; https://0-doi-org.brum.beds.ac.uk/10.3390/s21062092 - 17 Mar 2021

Cited by 4 | Viewed by 1916

Abstract

An imaging Fourier-transform spectrometer in the mid-infrared (1850–6667 cm

^{- 1}

) has been used to acquire transmittance spectra at a resolution of 1 cm

^{- 1}

of three atmospheric pollutants with known column densities (Q): methane (258 ppm·m), nitrous oxide (107.5 ppm·m) [...] Read more.

An imaging Fourier-transform spectrometer in the mid-infrared (1850–6667 cm

^{- 1}

) has been used to acquire transmittance spectra at a resolution of 1 cm

^{- 1}

of three atmospheric pollutants with known column densities (Q): methane (258 ppm·m), nitrous oxide (107.5 ppm·m) and propane (215 ppm·m). Values of Q and T have been retrieved by fitting them with theoretical spectra generated with parameters from the HITRAN database, based on a radiometric model that takes into account gas absorption and emission, and the instrument lineshape function. A principal component analysis (PCA) of experimental data has found that two principal components are enough to reconstruct gas spectra with high fidelity. PCA-processed spectra have better signal-to-noise ratio without loss of spatial resolution, improving the uniformity of retrieval. PCA has been used also to speed up retrieval, by pre-calculating simulated spectra for a range of expected Q and T values, applying PCA to them and then comparing the principal components of experimental spectra with those of the simulated ones to find the gas Q and T values. A reduction in calculation time by a factor larger than one thousand is achieved with improved accuracy. Retrieval can be further simplified by obtaining T and Q as quadratic functions of the two first principal components. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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22 pages, 13453 KiB

Open AccessArticle

Analytic Optimization of Cantilevers for Photoacoustic Gas Sensor with Capacitive Transduction

by Wioletta Trzpil, Nicolas Maurin, Roman Rousseau, Diba Ayache, Aurore Vicet and Michael Bahriz

Sensors 2021, 21(4), 1489; https://0-doi-org.brum.beds.ac.uk/10.3390/s21041489 - 21 Feb 2021

Cited by 10 | Viewed by 2458

Abstract

We propose a new concept of photoacoustic gas sensing based on capacitive transduction which allows full integration while conserving the required characteristics of the sensor. For the sensor’s performance optimization, trial and error method is not feasible due to economic and time constrains. Therefore, we focus on a theoretical optimization of the sensor reinforced by computational methods implemented in a Python programming environment. We present an analytic model to optimize the geometry of a cantilever used as a capacitive transducer in photoacoustic spectroscopy. We describe all the physical parameters which have to be considered for this optimization (photoacoustic force, damping, mechanical susceptibility, capacitive transduction, etc.). These parameters are characterized by opposite trends. They are studied and compared to obtain geometric values for which the signal output and signal-to-noise ratio are maximized. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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19 pages, 4104 KiB

Open AccessArticle

Spectroscopic Techniques versus Pitot Tube for the Measurement of Flow Velocity in Narrow Ducts

by Francesco D’Amato, Silvia Viciani, Alessio Montori, Marco Barucci, Carmen Morreale, Silvia Bertagna and Gabriele Migliavacca

Sensors 2020, 20(24), 7349; https://0-doi-org.brum.beds.ac.uk/10.3390/s20247349 - 21 Dec 2020

Cited by 2 | Viewed by 3051

Abstract

In order to assess the limits and applicability of Pitot tubes for the measurement of flow velocity in narrow ducts, e.g., biomass burning plants, an optical, dual function device was implemented. This sensor, based on spectroscopic techniques, targets a trace gas, injected inside the stack either in bursts, or continuously, so performing transit time or dilution measurements. A comparison of the two optical techniques with respect to Pitot readings was carried out in different flow conditions (speed, temperature, gas composition). The results of the two optical measurements are in agreement with each other and fit quite well the theoretical simulation of the flow field, while the results of the Pitot measurements show a remarkable dependence on position and inclination of the Pitot tube with respect to the duct axis. The implications for the metrology of small combustors’ emissions are outlined. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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Review

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35 pages, 3432 KiB

Open AccessReview

Integrated Nanophotonic Waveguide-Based Devices for IR and Raman Gas Spectroscopy

by Sebastián Alberti, Anurup Datta and Jana Jágerská

Sensors 2021, 21(21), 7224; https://0-doi-org.brum.beds.ac.uk/10.3390/s21217224 - 30 Oct 2021

Cited by 7 | Viewed by 4340

Abstract

On-chip devices for absorption spectroscopy and Raman spectroscopy have been developing rapidly in the last few years, triggered by the growing availability of compact and affordable tunable lasers, detectors, and on-chip spectrometers. Material processing that is compatible with mass production has been proven to be capable of long low-loss waveguides of sophisticated designs, which are indispensable for high-light–analyte interactions. Sensitivity and selectivity have been further improved by the development of sorbent cladding. In this review, we discuss the latest advances and challenges in the field of waveguide-enhanced Raman spectroscopy (WERS) and waveguide infrared absorption spectroscopy (WIRAS). The development of integrated light sources and detectors toward miniaturization will be presented, together with the recent advances on waveguides and cladding to improve sensitivity. The latest reports on gas-sensing applications and main configurations for WERS and WIRAS will be described, and the most relevant figures of merit and limitations of different sensor realizations summarized. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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25 pages, 5031 KiB

Open AccessReview

A Review of Antiresonant Hollow-Core Fiber-Assisted Spectroscopy of Gases

by Piotr Jaworski

Sensors 2021, 21(16), 5640; https://0-doi-org.brum.beds.ac.uk/10.3390/s21165640 - 21 Aug 2021

Cited by 12 | Viewed by 3660

Abstract

Antiresonant Hollow-Core Fibers (ARHCFs), thanks to the excellent capability of guiding light in an air core with low loss over a very broad spectral range, have attracted significant attention of researchers worldwide who especially focus their work on laser-based spectroscopy of gaseous substances. It was shown that the ARHCFs can be used as low-volume, non-complex, and versatile gas absorption cells forming the sensing path length in the sensor, thus serving as a promising alternative to commonly used bulk optics-based configurations. The ARHCF-aided sensors proved to deliver high sensitivity and long-term stability, which justifies their suitability for this particular application. In this review, the recent progress in laser-based gas sensors aided with ARHCFs combined with various laser-based spectroscopy techniques is discussed and summarized. Full article

(This article belongs to the Special Issue Optical Gas Sensing: Media, Mechanisms and Applications)

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