State-of-the-art Laser Gas Sensing Technologies

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Optics and Lasers".

Deadline for manuscript submissions: closed (30 May 2019) | Viewed by 72494

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150006, China
Interests: optical gas sensing; laser spectroscopy; laser technology
Special Issues, Collections and Topics in MDPI journals
Institute Of Electronics and Systems, CNRS, University of Montpellier, Montpellier, France
Interests: laser spectroscopy; QEPAS; resonant spectroscopy; single frequency lasers; tunable sources
Faculty of Electronics, Photonics and Microsystem, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
Interests: fiber lasers; nonlinear optics; laser spectroscopy

Special Issue Information

Dear Colleagues,

Trace gas sensing technologies are widely used in many applications, such as environmental monitoring, life science, medical diagnostics, and planetary exploration. Hence, gas sensors with high detection sensitivity and robust design are needed urgently. Gas sensing techniques with the advantages of high sensitivity, non-invasiveness and in situ, real-time observation fill a distinct gap between low-cost sensors with limited performance, such as electrochemical and semiconductor gas sensors, and expensive laboratory equipment, such as gas chromatographs and mass spectrometers. Therefore, in this Special Issue, papers about laser gas sensing techniques, in particular advanced methods, are welcomed. Review articles which describe the current state-of-the-art are also encouraged. Potential topics include, but are not limited to, the following:

  1. photoacoustic spectroscopy
  2. tunable diode laser spectroscopy
  3. cavity-enhanced spectroscopy
  4. laser-induced fluorescence spectroscopy
  5. laser Raman spectroscopy
  6. heterodyne laser spectroscopy
  7. photothermal spectroscopy
  8. optical sensing technique
  9. optical gas sensors applications
  10. dual comb spectroscopy
  11. tunable laser sources for spectroscopy

Prof. Dr. Yufei Ma
Dr. Aurore Vicet
Dr. Karol Krzempek
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 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

  • optical gas sensing
  • laser spectroscopy
  • high sensitivity
  • real-time observation
  • laser sources

Published Papers (17 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Editorial

Jump to: Research, Review

3 pages, 160 KiB  
Editorial
State-of-the-Art Laser Gas Sensing Technologies
by Yufei Ma, Aurore Vicet and Karol Krzempek
Appl. Sci. 2020, 10(2), 433; https://doi.org/10.3390/app10020433 - 07 Jan 2020
Cited by 4 | Viewed by 1914
Abstract
The increasing desire to detect and monitor in different fields [...] Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)

Research

Jump to: Editorial, Review

13 pages, 4649 KiB  
Article
High-Precision 13CO2/12CO2 Isotopic Ratio Measurement Using Tunable Diode Laser Absorption Spectroscopy at 4.3 μm for Deep-Sea Natural Gas Hydrate Exploration
by Hanquan Zhang, Mingming Wen, Yonghang Li, Peng Wan and Chen Chen
Appl. Sci. 2019, 9(17), 3444; https://doi.org/10.3390/app9173444 - 21 Aug 2019
Cited by 7 | Viewed by 2574
Abstract
For the detection of deep-sea natural gas hydrates, it is very important to accurately detect the 13CO2/12CO2 isotope ratio of dissolved gas in seawater. In this paper, a 13CO2/12CO2 isotope ratio [...] Read more.
For the detection of deep-sea natural gas hydrates, it is very important to accurately detect the 13CO2/12CO2 isotope ratio of dissolved gas in seawater. In this paper, a 13CO2/12CO2 isotope ratio sensor is investigated, which uses a tunable diode laser absorption spectroscopy (TDLAS) technique at 4.3 μm. The proposed sensor consists of a mid-infrared interband cascade laser (ICL) operating in continuous wave mode, a long optical path multi-pass gas cell (MPGC) of 24 m, and a mid-infrared mercury cadmium telluride (MCT) detector. Aiming at the problem of the strong absorption intensity of the two absorption lines of 13CO2 and 12CO2 being affected by temperature, a high-precision temperature control system for the MPGC was fabricated. Five different concentrations of CO2 gas were configured to calibrate the sensor, and the response linearity could reach 0.9992 for 12CO2 and 0.9996 for 13CO2. The data show that the carbon isotope measurement precision was assessed to be 0.0139‰ when the integration time was 92 s and the optical path length was 24 m. The sensor is combined with a gas–liquid separator to detect the 13CO2/12CO2 isotope ratio of CO2 gas extracted from water. Results validate the reported sensor system’s potential application in deep-sea natural gas hydrate exploration. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

11 pages, 3231 KiB  
Article
Near-Infrared C2H2 Detection System Based on Single Optical Path Time Division Multiplexing Differential Modulation Technique and Multi-Reflection Chamber
by Biao Wang, Hongfei Lu, Chen Chen, Lei Chen, Houquan Lian, Tongxin Dai and Yue Chen
Appl. Sci. 2019, 9(13), 2637; https://doi.org/10.3390/app9132637 - 28 Jun 2019
Cited by 6 | Viewed by 1861
Abstract
A time division multiplexing differential modulation technique is proposed to address the interference problem caused by the fluctuation of laser light intensity in the single optical path detection system. Simultaneously, a multi-reflection chamber is designed and manufactured to further improve the system’s precision [...] Read more.
A time division multiplexing differential modulation technique is proposed to address the interference problem caused by the fluctuation of laser light intensity in the single optical path detection system. Simultaneously, a multi-reflection chamber is designed and manufactured to further improve the system’s precision with an optical path length of 80 m. A near-infrared C2H2 detection system was developed. The absorption peak of the acetylene (C2H2) molecule near 1520 nm was selected as the absorption line. A laser driver is developed, and a lock-in amplifier is used to extract the second harmonic (2f) signal. A good linear relationship existed between C2H2 concentration and the 2f signal, and the correlation coefficient was 0.9997. In the detection range of 10–100 ppmv, the minimum detection limit was 0.3 ppmv, and the precision was 2%. At 50 ppmv, C2H2 and continuous detection for 10 h, the data average was 50.03 ppmv, and the fluctuation was less than ±1.2%. The Allan variance method was adopted to evaluate the long-term characteristic of the system. At 1 s of integration time, the Allan deviation was 0.3 ppmv. When the integration time reached 362 s, the Allan deviation was 0.0018 ppmv, which indicates the good stability of the detection system. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

10 pages, 2344 KiB  
Article
High-Efficiency Coupling Method of the Gradient-Index Fiber Probe and Hollow-Core Photonic Crystal Fiber
by Chi Wang, Yue Zhang, Jianmei Sun, Jinhui Li, Xinqun Luan and Anand Asundi
Appl. Sci. 2019, 9(10), 2073; https://doi.org/10.3390/app9102073 - 20 May 2019
Cited by 3 | Viewed by 2061
Abstract
A high-efficiency coupling method using the gradient-index (GRIN) fiber probe and hollow-core photonic crystal fiber (HC-PCF) is proposed to improve the response time and the sensitivity of gas sensors. A coupling efficiency model of the GRIN fiber probe coupled with HC-PCF is analyzed. [...] Read more.
A high-efficiency coupling method using the gradient-index (GRIN) fiber probe and hollow-core photonic crystal fiber (HC-PCF) is proposed to improve the response time and the sensitivity of gas sensors. A coupling efficiency model of the GRIN fiber probe coupled with HC-PCF is analyzed. An optimization method is proposed to guide the design of the probe and five samples of the GRIN fiber probe with different performances are designed, fabricated, and measured. Next, a coupling efficiency experimental system is established. The coupling efficiencies of the probes and single-mode fiber (SMF) are measured and compared. The experimental results corrected by image processing show that the GRIN fiber probe can achieve a coupling efficiency of 80.22% at distances up to 180 μm, which is obviously superior to the value of 33.45% of SMF at the same distance. Moreover, with the increase of the coupling distance, the coupling efficiency of the probe is still higher than that of SMF. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

15 pages, 2967 KiB  
Article
Methane Detection Based on Improved Chicken Algorithm Optimization Support Vector Machine
by Zhifang Wang, Shutao Wang, Deming Kong and Shiyu Liu
Appl. Sci. 2019, 9(9), 1761; https://doi.org/10.3390/app9091761 - 28 Apr 2019
Cited by 10 | Viewed by 2111
Abstract
Methane, known as a flammable and explosion hazard gas, is the main component of marsh gas, firedamp, and rock gas. Therefore, it is important to be able to detect methane concentration safely and effectively. At present, many models have been proposed to enhance [...] Read more.
Methane, known as a flammable and explosion hazard gas, is the main component of marsh gas, firedamp, and rock gas. Therefore, it is important to be able to detect methane concentration safely and effectively. At present, many models have been proposed to enhance the performance of methane predictions. However, the traditional models displayed inevitable shortcomings in parameter optimization in our experiment, which resulted in their having poor prediction performance. Accordingly, the improved chicken swarm algorithm optimized support vector machine (ICSO-SVM) was proposed to predict the concentration of methane precisely. The traditional chicken swarm optimization algorithm (CSO) easily falls into a local optimum due to its characteristics, so the ICSO algorithm was developed. The formula for position updating of the chicks of the ICSO is not only about the rooster of the same subgroup, but also about the roosters of other subgroups. Therefore, the ICSO algorithm more easily avoids falling into the local extremum. In this paper, the following work has been done. The sample data were obtained by using the methane detection system designed by us; In order to verify the validity of the ICSO algorithm, the ICSO, CSO, genetic algorithm (GA), and particle swarm optimization algorithm (PSO) algorithms were tested, and the four models were applied for methane concentration prediction. The results showed that he ICSO algorithm had the best convergence effect, relative error percentage, and average mean squared error, when the four models were applied to predict methane concentration. The results showed that the average mean squared error values of ICSO-SVM model were smaller than other three models, and that the ICSO-SVM model has better stability, and the average recovery rate of the ICSO-SVM is much closer to 100%. Therefore, the ICSO-SVM model can efficiently predict methane concentration. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Graphical abstract

15 pages, 4264 KiB  
Article
TDLAS Monitoring of Carbon Dioxide with Temperature Compensation in Power Plant Exhausts
by Xiaorui Zhu, Shunchun Yao, Wei Ren, Zhimin Lu and Zhenghui Li
Appl. Sci. 2019, 9(3), 442; https://doi.org/10.3390/app9030442 - 28 Jan 2019
Cited by 30 | Viewed by 4987
Abstract
Temperature variations of flue gas have an effect on carbon dioxide (CO2) emissions monitoring. This paper demonstrates accurate CO2 concentration measurement using tunable diode laser absorption spectroscopy (TDLAS) with temperature compensation methods. A distributed feedback diode laser at 1579 nm [...] Read more.
Temperature variations of flue gas have an effect on carbon dioxide (CO2) emissions monitoring. This paper demonstrates accurate CO2 concentration measurement using tunable diode laser absorption spectroscopy (TDLAS) with temperature compensation methods. A distributed feedback diode laser at 1579 nm was chosen as the laser source for CO2 measurements. A modeled flue gas was made referring to CO2 concentrations of 10–20% and temperatures of 298–338 K in the exhaust of a power plant. Two temperature compensation methods based on direct absorption (DA) and wavelength modulation (WMS) are presented to improve the accuracy of the concentration measurement. The relative standard deviations of DA and WMS measurements of concentration were reduced from 0.84% and 0.35% to 0.42% and 0.31%, respectively. Our experimental results have validated the rationality of temperature compensations and can be further applied for high-precision measurement of gas concentrations in industrial emission monitoring. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

14 pages, 3568 KiB  
Article
Real-Time Vision through Haze Based on Polarization Imaging
by Xinhua Wang, Jihong Ouyang, Yi Wei, Fei Liu and Guang Zhang
Appl. Sci. 2019, 9(1), 142; https://doi.org/10.3390/app9010142 - 03 Jan 2019
Cited by 17 | Viewed by 4078
Abstract
Various gases and aerosols in bad weather conditions can cause severe image degradation, which will seriously affect the detection efficiency of optical monitoring stations for high pollutant discharge systems. Thus, penetrating various gases and aerosols to sense and detect the discharge of pollutants [...] Read more.
Various gases and aerosols in bad weather conditions can cause severe image degradation, which will seriously affect the detection efficiency of optical monitoring stations for high pollutant discharge systems. Thus, penetrating various gases and aerosols to sense and detect the discharge of pollutants plays an important role in the pollutant emission detection system. Against this backdrop, we recommend a real-time optical monitoring system based on the Stokes vectors through analyzing the scattering characteristics and polarization characteristics of both gases and aerosols in the atmosphere. This system is immune to the effects of various gases and aerosols on the target to be detected and achieves the purpose of real-time sensing and detection of high pollutant discharge systems under bad weather conditions. The imaging system is composed of four polarizers with different polarization directions integrated into independent cameras aligned parallel to the optical axis in order to acquire the Stokes vectors from various polarized azimuth images. Our results show that this approach achieves high-contrast and high-definition images in real time without the loss of spatial resolution in comparison with the performance of conventional imaging techniques. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

11 pages, 1805 KiB  
Article
Investigating the Relation between Absorption and Gas Concentration in Gas Detection Using a Diffuse Integrating Cavity
by Xue Zhou, Jia Yu, Lin Wang and Zhiguo Zhang
Appl. Sci. 2018, 8(9), 1630; https://doi.org/10.3390/app8091630 - 12 Sep 2018
Cited by 5 | Viewed by 3250
Abstract
The relationship between absorption and gas concentration was studied using a diffuse integrating cavity as a gas cell. The light transmission process in an arbitrary diffuse cavity was theoretically derived based on a beam reflection analysis. It was found that a weak absorption [...] Read more.
The relationship between absorption and gas concentration was studied using a diffuse integrating cavity as a gas cell. The light transmission process in an arbitrary diffuse cavity was theoretically derived based on a beam reflection analysis. It was found that a weak absorption condition must be satisfied to ensure a linear relationship between absorbance and gas concentration. When the weak absorption condition is not satisfied, a non-linear relation will be observed. A 35 × 35 × 35 cm diffuse integrating cavity was used in the experiment. Different oxygen concentrations were measured by detecting the P9 absorption line at 763.8 nm, based on tunable diode laser absorption spectroscopy. The relationship between the absorption signals and oxygen concentration was linear at low oxygen concentrations and became non-linear when oxygen concentrations were higher than 21%. The absorbance value of this transition point was 0.17, which was considered as the weak absorption condition for this system. This work studied the theoretical reason for the non-linear phenomenon and provided an experimental method to determine the transition point when using a diffuse integrating cavity as a gas cell. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Graphical abstract

7 pages, 1751 KiB  
Communication
Watt-Level Continuous-Wave Single-Frequency Mid-Infrared Optical Parametric Oscillator Based on MgO:PPLN at 3.68 µm
by Jiaqun Zhao, Ping Cheng, Feng Xu, Xiaofeng Zhou, Jun Tang, Yong Liu and Guodong Wang
Appl. Sci. 2018, 8(8), 1345; https://doi.org/10.3390/app8081345 - 10 Aug 2018
Cited by 18 | Viewed by 3842
Abstract
We report a continuous-wave single-frequency singly-resonant mid-infrared optical parametric oscillator (OPO). The OPO is based on 5 mol % MgO-doped periodically poled lithium niobate (MgO:PPLN) pumped by a continuous-wave single-frequency Nd:YVO4 laser at 1064 nm. A four-mirror bow-tie ring cavity configuration is [...] Read more.
We report a continuous-wave single-frequency singly-resonant mid-infrared optical parametric oscillator (OPO). The OPO is based on 5 mol % MgO-doped periodically poled lithium niobate (MgO:PPLN) pumped by a continuous-wave single-frequency Nd:YVO4 laser at 1064 nm. A four-mirror bow-tie ring cavity configuration is adopted. A low-finesse intracavity etalon is utilized to compress the linewidth of the resonant signal. A single-frequency idler output power higher than 1 W at 3.68 µm is obtained. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

8 pages, 3070 KiB  
Article
Passively Q-Switched Operation of a Tm,Ho:LuVO4 Laser with a Graphene Saturable Absorber
by Wei Wang, Linjun Li, Hongtian Zhang, Jinping Qin, Yuang Lu, Chong Xu, Shasha Li, Yingjie Shen, Wenlong Yang, Yuqiang Yang and Xiaoyang Yu
Appl. Sci. 2018, 8(6), 954; https://doi.org/10.3390/app8060954 - 09 Jun 2018
Cited by 10 | Viewed by 3005
Abstract
A passively Q-switched (PQS) operation of Tm,Ho:LuVO4 laser is experimentally demonstrated with a graphene saturable absorber (SA) mirror. An average output power of 1034 mW at 54.5 kHz is acquired with an 8% optical–optical conversion efficiency. The energy per pulse of 40.4 [...] Read more.
A passively Q-switched (PQS) operation of Tm,Ho:LuVO4 laser is experimentally demonstrated with a graphene saturable absorber (SA) mirror. An average output power of 1034 mW at 54.5 kHz is acquired with an 8% optical–optical conversion efficiency. The energy per pulse of 40.4 μJ and a peak power of 56.07 W are achieved; the narrowest pulse width of 300 ns is acquired, and the output wavelengths of Tm,Ho:LuVO4 are 2075.02 nm in a continuous wave (CW) regime and 2057.03 nm in a PQS regime. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

14 pages, 4797 KiB  
Article
A Tunable Mid-Infrared Solid-State Laser with a Compact Thermal Control System
by Deyang Yu, Yang He, Kuo Zhang, Qikun Pan, Fei Chen and Lihong Guo
Appl. Sci. 2018, 8(6), 878; https://doi.org/10.3390/app8060878 - 26 May 2018
Cited by 6 | Viewed by 3831
Abstract
Tunable mid-infrared lasers are widely used in laser spectroscopy, gas sensing and many other related areas. In order to solve heat dissipation problems and improve the environmental temperature adaptability of solid-state laser sources, a tunable all-fiber laser pumped optical parametric oscillator (OPO) was [...] Read more.
Tunable mid-infrared lasers are widely used in laser spectroscopy, gas sensing and many other related areas. In order to solve heat dissipation problems and improve the environmental temperature adaptability of solid-state laser sources, a tunable all-fiber laser pumped optical parametric oscillator (OPO) was established, and a compact thermal control system based on thermoelectric coolers, an automatic temperature control circuit, cooling fins, fans and heat pipes was integrated and designed for the laser. This system is compact, light and air-cooling which satisfies the demand for miniaturization of lasers. A mathematical model and method was established to estimate the cooling capacity of this thermal control system under different ambient environments. A finite-element model was built and simulated to analyze the thermal transfer process. Experiments in room and high temperature environments were carried out and showed that the substrate temperature of a pump module could be maintained at a stable value with controlled precision to 0.2 degrees, while the output power stability of the laser was within ±1%. The experimental results indicate that this compact air-cooling thermal control system could effectively solve the heat dissipation problem of mid-infrared solid-state lasers with a one hundred watts level pump module in room and high temperature environments. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

Review

Jump to: Editorial, Research

19 pages, 4065 KiB  
Review
A Review of Photothermal Detection Techniques for Gas Sensing Applications
by Karol Krzempek
Appl. Sci. 2019, 9(14), 2826; https://doi.org/10.3390/app9142826 - 15 Jul 2019
Cited by 28 | Viewed by 5561
Abstract
Photothermal spectroscopy (PTS) is a technique used for determining the composition of liquids, solids and gases. In PTS, the sample is illuminated with a radiation source, and the thermal response of the analyte (e.g., refractive index) is analyzed to gain information about its [...] Read more.
Photothermal spectroscopy (PTS) is a technique used for determining the composition of liquids, solids and gases. In PTS, the sample is illuminated with a radiation source, and the thermal response of the analyte (e.g., refractive index) is analyzed to gain information about its content. Recent advances in this unique method of detecting gaseous samples show that photothermal gas spectroscopy can be an interesting alternative to commonly used absorption techniques. Moreover, if designed properly, sensors using PTS detection technique can not only reach sensitivities comparable with other, more complex techniques, but can significantly simplify the design of the sensor. In this review, recent developments in photothermal spectroscopy of gases will be summarized and discussed. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Graphical abstract

16 pages, 1998 KiB  
Review
Recent Developments in Modulation Spectroscopy for Methane Detection Based on Tunable Diode Laser
by Fei Wang, Shuhai Jia, Yonglin Wang and Zhenhua Tang
Appl. Sci. 2019, 9(14), 2816; https://doi.org/10.3390/app9142816 - 15 Jul 2019
Cited by 36 | Viewed by 4770
Abstract
In this review, methane absorption characteristics mainly in the near-infrared region and typical types of currently available semiconductor lasers are described. Wavelength modulation spectroscopy (WMS), frequency modulation spectroscopy (FMS), and two-tone frequency modulation spectroscopy (TTFMS), as major techniques in modulation spectroscopy, are presented [...] Read more.
In this review, methane absorption characteristics mainly in the near-infrared region and typical types of currently available semiconductor lasers are described. Wavelength modulation spectroscopy (WMS), frequency modulation spectroscopy (FMS), and two-tone frequency modulation spectroscopy (TTFMS), as major techniques in modulation spectroscopy, are presented in combination with the application of methane detection. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

27 pages, 5611 KiB  
Review
Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization
by Zhenhai Wang, Pengfei Fu and Xing Chao
Appl. Sci. 2019, 9(13), 2723; https://doi.org/10.3390/app9132723 - 05 Jul 2019
Cited by 55 | Viewed by 5592
Abstract
Laser absorption spectroscopy (LAS) is a promising diagnostic method capable of providing high-bandwidth, species-specific sensing, and highly quantitative measurements. This review aims at providing general guidelines from the perspective of LAS sensor system design for realizing quantitative species diagnostics in combustion-related environments. A [...] Read more.
Laser absorption spectroscopy (LAS) is a promising diagnostic method capable of providing high-bandwidth, species-specific sensing, and highly quantitative measurements. This review aims at providing general guidelines from the perspective of LAS sensor system design for realizing quantitative species diagnostics in combustion-related environments. A brief overview of representative detection limits and bandwidths achieved in different measurement scenarios is first provided to understand measurement needs and identify design targets. Different measurement schemes including direct absorption spectroscopy (DAS), wavelength modulation spectroscopy (WMS), and their variations are discussed and compared in terms of advantages and limitations. Based on the analysis of the major sources of noise including electronic, optical, and environmental noises, strategies of noise reduction and design optimization are categorized and compared. This addresses various means of laser control parameter optimization and data processing algorithms such as baseline extraction, in situ laser characterization, and wavelet analysis. There is still a large gap between the current sensor capabilities and the demands of combustion and engine diagnostic research. This calls for a profound understanding of the underlying fundamentals of a LAS sensing system in terms of optics, spectroscopy, and signal processing. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

25 pages, 3785 KiB  
Review
A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics
by Bo Li, Dayuan Zhang, Jixu Liu, Yifu Tian, Qiang Gao and Zhongshan Li
Appl. Sci. 2019, 9(9), 1906; https://doi.org/10.3390/app9091906 - 09 May 2019
Cited by 25 | Viewed by 6701
Abstract
The applications of femtosecond lasers to the diagnostics of combustion and flow field have recently attracted increasing interest. Many novel spectroscopic methods have been developed in obtaining non-intrusive measurements of temperature, velocity, and species concentrations with unprecedented possibilities. In this paper, several applications [...] Read more.
The applications of femtosecond lasers to the diagnostics of combustion and flow field have recently attracted increasing interest. Many novel spectroscopic methods have been developed in obtaining non-intrusive measurements of temperature, velocity, and species concentrations with unprecedented possibilities. In this paper, several applications of femtosecond-laser-based incoherent techniques in the field of combustion diagnostics were reviewed, including two-photon femtosecond laser-induced fluorescence (fs-TPLIF), femtosecond laser-induced breakdown spectroscopy (fs-LIBS), filament-induced nonlinear spectroscopy (FINS), femtosecond laser-induced plasma spectroscopy (FLIPS), femtosecond laser electronic excitation tagging velocimetry (FLEET), femtosecond laser-induced cyano chemiluminescence (FLICC), and filamentary anemometry using femtosecond laser-extended electric discharge (FALED). Furthermore, prospects of the femtosecond-laser-based combustion diagnostic techniques in the future were analyzed and discussed to provide a reference for the relevant researchers. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

33 pages, 1444 KiB  
Review
Mid-Infrared Tunable Laser-Based Broadband Fingerprint Absorption Spectroscopy for Trace Gas Sensing: A Review
by Zhenhui Du, Shuai Zhang, Jinyi Li, Nan Gao and Kebin Tong
Appl. Sci. 2019, 9(2), 338; https://doi.org/10.3390/app9020338 - 18 Jan 2019
Cited by 114 | Viewed by 9872
Abstract
The vast majority of gaseous chemical substances exhibit fundamental rovibrational absorption bands in the mid-infrared spectral region (2.5–25 μm), and the absorption of light by these fundamental bands provides a nearly universal means for their detection. A main feature of optical techniques is [...] Read more.
The vast majority of gaseous chemical substances exhibit fundamental rovibrational absorption bands in the mid-infrared spectral region (2.5–25 μm), and the absorption of light by these fundamental bands provides a nearly universal means for their detection. A main feature of optical techniques is the non-intrusive in situ detection of trace gases. We reviewed primarily mid-infrared tunable laser-based broadband absorption spectroscopy for trace gas detection, focusing on 2008–2018. The scope of this paper is to discuss recent developments of system configuration, tunable lasers, detectors, broadband spectroscopic techniques, and their applications for sensitive, selective, and quantitative trace gas detection. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

15 pages, 14159 KiB  
Review
Review of Recent Advances in QEPAS-Based Trace Gas Sensing
by Yufei Ma
Appl. Sci. 2018, 8(10), 1822; https://doi.org/10.3390/app8101822 - 04 Oct 2018
Cited by 68 | Viewed by 4996
Abstract
Quartz-enhanced photoacoustic spectroscopy (QEPAS) is an improvement of the conventional microphone-based photoacoustic spectroscopy. In the QEPAS technique, a commercially available millimeter-sized piezoelectric element quartz tuning fork (QTF) is used as an acoustic wave transducer. With the merits of high sensitivity and selectivity, low [...] Read more.
Quartz-enhanced photoacoustic spectroscopy (QEPAS) is an improvement of the conventional microphone-based photoacoustic spectroscopy. In the QEPAS technique, a commercially available millimeter-sized piezoelectric element quartz tuning fork (QTF) is used as an acoustic wave transducer. With the merits of high sensitivity and selectivity, low cost, compactness, and a large dynamic range, QEPAS sensors have been applied widely in gas detection. In this review, recent developments in state-of-the-art QEPAS-based trace gas sensing technique over the past five years are summarized and discussed. The prospect of QEPAS-based gas sensing is also presented. Full article
(This article belongs to the Special Issue State-of-the-art Laser Gas Sensing Technologies)
Show Figures

Figure 1

Back to TopTop