Hollow waveguide-enhanced mid-infrared sensor for fast and sensitive ethylene detection

Sensor Review ◽  
2017 ◽  
Vol 37 (1) ◽  
pp. 82-87 ◽  
Author(s):  
Jinyi Li ◽  
Zhenhui Du ◽  
Zheyuan Zhang ◽  
Limei Song ◽  
Qinghua Guo
Keyword(s):  
Second Harmonic ◽  
Tunable Laser ◽  
Infrared Region ◽  
Integration Time ◽  
Hollow Waveguide ◽  
Gas Cell ◽  
Optical Source ◽  
Mid Infrared ◽  
Content Type ◽  
Sensor Platform

Purpose This paper aims to provide a sensor for fast, sensitive and selective ethylene (C2H4) concentration measurements. Design/methodology/approach The paper developed a sensor platform based on tunable laser absorption spectroscopy with a 3,266-nm interband cascade laser (ICL) as an optical source and a hollow waveguide (HWG) as a gas cell. The ICL wavelength was scanned across a C2H4 strong fundamental absorption band, and an interference-free C2H4 absorption line located at 3,060.76 cm−1 was selected. Wavelength modulation spectroscopy with the second harmonic detection (WMS-2f) technique was used to improve the sensitivity. Furthermore, the HWG gas cell can achieve a long optical path in a very small volume to improve the time response. Findings The results show excellent linearity of the measured 2f signal and the C2H4 concentration with a correlation coefficient of 0.9997. Also, the response time is as short as about 10 s. The Allan variance analysis indicates that the detection limit can achieve 53 ppb with an integration time of 24 s. Practical implications The ethylene sensor has many meaningful applications in environmental monitoring, industrial production, national security and the biomedicine field. Originality/value The paper provides a novel sensor architecture which can be a versatile sensor platform for fast and sensitive trace-gas detection in the mid-infrared region.

scholarly journals A Laser-Based Multipass Absorption Sensor for Sub-ppm Detection of Methane, Acetylene and Ammonia

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 556
Author(s):  
Wei Duan ◽  
Fuwu Yan ◽  
Yu Wang ◽  
Hui Zhang ◽  
Liuhao Ma ◽  
...  
Keyword(s):  
Detection Limit ◽  
Second Harmonic ◽  
Beam Steering ◽  
Optical Path Length ◽  
Integration Time ◽  
Gas Cell ◽  
Long Term Stability ◽  
Deviation Analysis ◽  
Time Flow ◽  
Sampling Volume

A compact, sensitive laser-based absorption sensor for multispecies monitoring of methane (CH4), acetylene (C2H2) and ammonia (NH3) was developed using a compact multipass gas cell. The gas cell is 8.8 cm long and has an effective optical path length of 3.0 m with a sampling volume of 75 mL. The sensor is composed of three fiber-coupled distributed feedback lasers operating near 1512 nm, 1532 nm and 1654 nm, an InGaAs photodetector and a custom-designed software for data acquisition, signal processing and display. The lasers were scanned over the target absorption features at 1 Hz. First-harmonic-normalized wavelength modulation spectroscopy (f = 3 kHz) with the second harmonic detection (WMS-2f/1f) is employed to eliminate the unwanted power fluctuations of the transmitted laser caused by aerosol/particles scattering, absorption and beam-steering. The multispecies sensor has excellent linear responses (R2 > 0.997) within the gas concentration range of 1–1000 ppm and shows a detection limit of 0.32 ppm for CH4, 0.16 ppm for C2H2 and 0.23 ppm for NH3 at 1 s response time. The Allan–Werle deviation analysis verifies the long-term stability of the sensor, indicating a minimal detection limit of 20–34 ppb were achieved after 60–148 s integration time. Flow test of the portable multispecies sensor is also demonstrated in this work.

Characterization of a Mid-Infrared Hollow Waveguide Gas Cell for the Analysis of Carbon Monoxide and Nitric Oxide

2006 ◽  
Vol 60 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Bruce T. Thompson ◽  
A. Inberg ◽  
N. Croitoru ◽  
Boris Mizaikoff
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Hollow Waveguide ◽  
Gas Cell ◽  
Mid Infrared

scholarly journals Near-Infrared Tunable Laser Absorption Spectroscopic Acetylene Sensor System Using a Novel Three Mirror-Based, Dense Pattern Gas Cell

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1266 ◽  
Author(s):  
Guoqiang Zhong ◽  
Zhuo Ma ◽  
Junbo Wang ◽  
Chuantao Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Path Length ◽  
Near Infrared ◽  
Limit Of Detection ◽  
Second Harmonic ◽  
Tunable Laser ◽  
Position Angle ◽  
Optical Path ◽  
Sensor System ◽  
Gas Cell ◽  
Dense Pattern

By contrast with the widely reported traditional two mirror-based Herriott cell, a three mirror-based dense pattern gas cell was proposed, of which the modeling and design were proven to be effective through a comparison between the simulated spot pattern and effective path length and those of the experimental results. A mechanical structure was designed to adjust the position/angle of the three mirrors for aligning the optical path. The experimentally measured reflection number was 60, resulting in an optical path length of ~11 m, which agrees well with the theoretical value of 10.95 m. Combined with a near-infrared laser with a center wavenumber located at an acetylene (C2H2) absorption line of 6521.2 cm−1, a C2H2 sensor system was established to verify the feasibility of the three mirror-based gas cell. Assisted by a data acquisition (DAQ) card, a LabVIEW platform was developed to generate the drive signal of the laser and acquire the second harmonic (2f) signal from the output of the detector. Through Allan variance analysis, the limit of detection (LoD) of the sensor system is 4.36 ppm at an average time of 0.5 s; as the average time exceeds 10 s, the LoD is <1 ppm. The proposed model and design of the three mirror-based gas cell can be used to realize similar gas cells with different absorption path lengths for gas detection based on infrared absorption spectroscopy.

Mid and near Infrared Study of Carbohydrates by Canonical Correlation Analysis

1993 ◽  
Vol 1 (2) ◽  
pp. 99-108 ◽  
Author(s):  
P. Robert ◽  
M.F. Devaux ◽  
A. Qannari ◽  
M. Safar
Keyword(s):  
Correlation Analysis ◽  
Infrared Spectra ◽  
Canonical Correlation ◽  
Near Infrared ◽  
Sugar Content ◽  
Infrared Region ◽  
Total Sugar ◽  
Mid Infrared ◽  
Total Sugar Content ◽  
Near Infrared Spectra

Multivariate data treatments were applied to mid and near infrared spectra of glucose, fructose and sucrose solutions in order to specify near infrared frequencies that characterise each carbohydrate. As a first step, the mid and near infrared regions were separately studied by performing Principal Component Analyses. While glucose, fructose and sucrose could be clearly identified on the similarity maps derived from the mid infrared spectra, only the total sugar content of the solutions was observed when using the near infrared region. Characteristic wavelengths of the total sugar content were found at 2118, 2270 and 2324 nm. In a second step, the mid and near infrared regions were jointly studied by a Canonical Correlation Analysis. As the assignments of frequencies are generally well known in the mid infrared region, it should be useful to study the relationships between the two infrared regions. Thus, the canonical patterns obtained from the near infrared spectra revealed wavelengths that characterised each carbohydrate. The OH and CH combination bands were observed at: 2088 and 2332 nm for glucose, 2134 and 2252 nm for fructose, 2058 and 2278 nm for sucrose. Although a precise assignment of the near infrared bands to chemical groups within the molecules was not possible, the present work showed that near infrared spectra of carbohydrates presented specific features.

Ortho-deuterium Raman laser using the S/sub 0/(2) rotational transition in the mid-infrared region

1997 ◽  
Vol 33 (12) ◽  
pp. 2174-2177 ◽  
Author(s):  
T. Takasaki ◽  
A. Suda ◽  
K. Sato ◽  
T. Shinozaki ◽  
K. Nagasaka ◽  
...  
Keyword(s):  
Raman Laser ◽  
Infrared Region ◽  
Rotational Transition ◽  
Mid Infrared

An efficient application of PML in fourth-order precise integration time domain method for the numerical solution of Maxwell's equations

2013 ◽  
Vol 33 (1/2) ◽  
pp. 116-125
Author(s):  
Zhongming Bai ◽  
Xikui Ma ◽  
Xu Zhuansun ◽  
Qi Liu
Keyword(s):  
Finite Difference ◽  
Numerical Solution ◽  
Fourth Order ◽  
Time Domain ◽  
Fdtd Method ◽  
Time Domain Method ◽  
Integration Time ◽  
Precise Integration ◽  
Content Type ◽  
Domain Method

Purpose – The purpose of the paper is to introduce a perfectly matched layer (PML) absorber, based on Berenger's split field PML, to the recently proposed low-dispersion precise integration time domain method using a fourth-order accurate finite difference scheme (PITD(4)). Design/methodology/approach – The validity and effectiveness of the PITD(4) method with the inclusion of the PML is investigated through a two-dimensional (2-D) point source radiating example. Findings – Numerical results indicate that the larger time steps remain unchanged in the procedure of the PITD(4) method with the PML, and meanwhile, the PITD(4) method employing the PML is of the same absorbability as that of the finite-difference time-domain (FDTD) method with the PML. In addition, it is also demonstrated that the later time reflection error of the PITD(4) method employing the PML is much lower than that of the FDTD method with the PML. Originality/value – An efficient application of PML in fourth-order precise integration time domain method for the numerical solution of Maxwell's equations.

Microstructure and thermal stability of amorphous materials in the GeS2−La2S3 system

1991 ◽  
Vol 6 (12) ◽  
pp. 2694-2700 ◽  
Author(s):  
Prashant N. Kumta ◽  
Subhash H. Risbud
Keyword(s):  
Thermal Stability ◽  
Amorphous Materials ◽  
Fiber Optic ◽  
Molecular Level ◽  
Infrared Region ◽  
Mid Infrared ◽  
Heat Treated ◽  
Stable Glasses ◽  
Microstructural Studies ◽  
Thermal Stability Of

GeS2 is known to be a good chalcogenide glass former with a transmission cutoff at 11 μm and has been studied for fiber optic application in the mid infrared region. The rare earth sulfides, oxysulfides, and oxides (La–Er) form reasonably good and stable glasses when mixed with chalcogenides such as Ga2S3. In this work, glass formation was studied in the GeS2−La2S3 system. Two compositions containing 60 mol % and 92.5 mol % GeS2, respectively, were analyzed, and the effects of composition on the microstructure and thermal stability of these glasses were investigated. Microstructural studies were conducted on the as-prepared and heat-treated glasses using TEM and SEM/EDXA. Glasses rich in GeS2 exhibited primary (6–88 nm) and secondary (3–13 nm) phase separation at the molecular level. Differential thermal analysis performed on these glasses indicated glass transition temperatures (Tg) of 510 °C and 420 °C for the two compositions studied. The glasses were stable and the (Tg) was observed to decrease with increasing contents of GeS2 in these glasses.

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