An external-cavity quantum cascade laser operating near 5.2<i>µ</i>m combined with cavity ring-down spectroscopy for multi-component chemical sensing

Banik, Gourab Dutta; Maity, Abhijit; Som, Suman; Pal, Mithun; Pradhan, Manik

doi:10.1088/1555-6611/aaaa55

Cited by 16 publications

(12 citation statements)

References 32 publications

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“…As mentioned above, high-resolution measurements of l-doublet splittings of OCS were made using the cw-CRDS method coupled with an EC-QCL operating at λ∼5.2 μm (1923 cm −1 ). The experimental arrangement of the cw-CRDS system has been described in detail previously [16][17][18][19] and therefore only salient features of the spectrometer are given here. In a classical cw-CRDS system, the decay rate of a laser light trapped in a highfinesse optical cavity is measured and the direct absorption of molecular spectral lines is recorded.…”

Section: Experimental Techniquementioning

confidence: 99%

Cavity ring-down spectroscopy measurements ofl-type doubling of hot bands in Δ vibrational states of OCS near 5.2μm

et al. 2018

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We investigated the l-type doubling in the (14 2 0)←(02 2 0) weak hot band transition of carbonyl sulphide (OCS) for l=2 (i.e. Δ state) vibrational state. High-resolution spectroscopic measurements of l-doublet splittings of OCS were carried out using cavity ring-down spectroscopy (CRDS) technique employing a continuous-wave (cw) external-cavity quantum cascade laser (EC-QCL) operating at ∼5.2 μm. The rotationally resolved spectra of l-doublet splittings between the parity doublet e and f sub-states of OCS were recorded by probing the rotational lines from J=22 to J=29 in the R branch belonging to the weak hot band transition. Subsequently, we determined the l-type doubling constant, transition dipole moment, rotational constant and centrifugal distortion constant for both e and f components of the (14 2 0) vibrational state with relatively high rotational states of OCS. As the measurement of l-doublet splitting in l=2 or higher states of OCS remains challenging due to extremely small splitting, therefore our findings suggest that the observation of the l-type doubling in Δ vibrational state (l=2) with new values of the several spectroscopic parameters as mentioned above will be useful for better understanding of linear polyatomic molecular properties in general from high-resolution spectroscopic data.

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Section: Experimental Techniquementioning

confidence: 99%

Cavity ring-down spectroscopy measurements ofl-type doubling of hot bands in Δ vibrational states of OCS near 5.2μm

et al. 2018

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Section: Introductionmentioning

confidence: 99%

“…At present, a great deal of experimental research is focused on trace gases in the atmosphere, such as H 2 O, C 2 H 4 , CH 4 , C 2 H 6 , CO, CO 2 , NH 3 , NO, NO 2 , NO 3 , N 2 O 5 , and other gaseous substances and their related isotopes. [3][4][5][6][7][8][9][10][11][12] For continuous-wave CRDS (CW-CRDS), a probe light with a single frequency is injected into a high-finesse cavity. The optical field propagating forth and back in the cavity will interact with the injection light.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Analysis and Numerical Simulation for Cavity Ring‐Down Spectroscopy

Yang

2021

Advanced Photonics Research

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To investigate the process of the creation of the ring‐down events in cavity ring‐down spectroscopy, theoretical formulae are derived for the interaction of the field in a cavity with the injection light, and a corresponding program for numerical simulation is developed. Using these theoretical formulas, the effects of the frequency detuning between the injection and the cavity mode, the absorption of the medium in the cavity, the residual injection, and the oscillation of the high‐order transverse modes are analyzed. A specific method for improving the measurement of the ring‐down time is proposed. With numerical simulation, the phenomenon of the intensity modulation during the frequency coupling of the cavity mode with the injection light is investigated. As the coherence of the injection light degrades, the light distribution in the cavity gradually develops from a smooth state to random states. Finally, it converges to a state at which the injection light is incoherent. The simple experimental results confirm that the limited coherence of the injection light causes the randomness of the development of the cavity field, and the results are used for the demonstration of the effectiveness and accuracy of the proposed method in solving for the ring‐down time.

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“…Recently, a quantum cascade laser was employed for long-path absorption spectroscopy (QCLS), cavity ring-down spectroscopy (CRDS), and off-axis integrated cavity output spectroscopy (OA-ICOS) to monitor COS, and the estimated limits of detection (LODs) were reported as 250 36 or 0.185 ppbv. 37 Kooijmans et al evaluated a QCLS for COS measurement at an ambient level of around 0.5 ppbv. 38 OA-ICOS has been recently developed to continuously measure dissolved COS in seawater with the use of an equilibrator.…”

Section: Introductionmentioning

confidence: 99%

Measurement Device for Ambient Carbonyl Sulfide by Means of Catalytic Reduction Followed by Wet Scrubbing/Fluorescence Detection

Abe

Shimohira

Miki³

et al. 2020

ACS Omega

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A portable chemical analysis system for monitoring ambient carbonyl sulfide (COS) was investigated for the first time. COS is paid attention to from the perspectives of photosynthesis tracer, breath diagnosis marker, and new process-use in the manufacture of semiconductors. Recently, the threshold level value of COS was settled at 5 ppm in volume ratio (ppmv) for workplace safety management. In this work, COS was converted to H 2 S by a small column packed with alumina catalyzer at 65 °C. Then, the H 2 S produced was collected in a small channel scrubber to react with fluorescein mercuric acetate (FMA), and the resulting fluorescence quenching was monitored using an LED/photodiode-based miniature detector. The miniature channel scrubber was re-examined to determine its robustness and easy fabrication, and conditions of the catalyzer were optimized. When the FMA concentration used was 1 μM, the limit of detection and dynamic range, which were both proportional to the FMA concentration, were 0.07 and 25 ppbv, respectively. Ambient COS in the background level and even contaminated COS in the nitrogen gas cylinder could be detected. If necessary, H 2 S was removed selectively by reproducible adsorbent columns. COS concentrations of engine exhaust were measured by the proposed method and by cryo-trap-gas chromatography-flame photometric detection, and the results obtained (0.5–5.9 ppbv) by the two methods agreed well ( R 2 = 0.945, n = 19). COS in ambient air and exhaust gases was successfully measured without any batchwise pretreatment.

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An external-cavity quantum cascade laser operating near 5.2µm combined with cavity ring-down spectroscopy for multi-component chemical sensing

Cited by 16 publications

References 32 publications

Cavity ring-down spectroscopy measurements ofl-type doubling of hot bands in Δ vibrational states of OCS near 5.2μm

Cavity ring-down spectroscopy measurements ofl-type doubling of hot bands in Δ vibrational states of OCS near 5.2μm

Theoretical Analysis and Numerical Simulation for Cavity Ring‐Down Spectroscopy

Measurement Device for Ambient Carbonyl Sulfide by Means of Catalytic Reduction Followed by Wet Scrubbing/Fluorescence Detection

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