Broadening-independent demodulation for wavelength modulation spectroscopy based on even-order harmonics

Chen, Wei; Wu, Yue; Luo, Yue

doi:10.1080/00387010.2017.1422523

Cited by 3 publications

(1 citation statement)

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“…When the target absorption is interfered by nearby transitions, the result of the multi-parameter fitting cannot be always unique, as the iterations can be converged to the local optimum instead of the global one. To address these issues, Chen et al [11] recently proposed to use the peak values of zero-, second-, and fourth-order harmonics, enabling the direct and fast measurement without complex simulations and curve fittings. However, Chen's algorithm is derived from the Lorentzian lineshape function, which is not applicable in low-pressure scenarios.…”

Section: Introductionmentioning

confidence: 99%

Calibration-free wavelength modulation spectroscopy based on even-order harmonics

Wang¹,

Zhou²,

Liu

2021

Opt. Express

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This paper proposes a novel and rapid calibration-free wavelength modulation spectroscopy algorithm based on even-order harmonics. The proposed algorithm, analytically deduced from Voigt line-shape function, only involves simple algebraic operations to describe the actual gas absorption spectra, thus eliminating the time-consuming simulations and lineshape fitting procedures adopted in traditional algorithms. Instead of acquiring the entirely scanned absorption line-shape, the proposed technique only requires extraction of the peak values of the harmonics. This characteristic significantly benefits gas diagnosis at elevated pressure and/or temperature, in which the entirely scanned absorption is very difficult to be obtained due to the broadened line-shapes. The proposed algorithm is validated by both numerical simulation and condition-controlled experiment, indicating millisecond-level calculation of gas parameters with the relative error less than 4% in the experiments.

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Section: Introductionmentioning

confidence: 99%