Baseline-free quantitative absorption spectroscopy based on cepstral analysis
Baseline-free quantitative absorption spectroscopy based on cepstral analysis
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DOI：
10.1364/oe.27.037920
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发表时间：
2019-12-23
期刊：
影响因子：
3.8
通讯作者：
Rieker, Gregory B.
中科院分区：
文献类型：
--
作者：
Cole, Ryan K.;Makowiecki, Amanda S.;Rieker, Gregory B.
定量吸收光谱的准确性取决于正确区分测量的透射光谱中的分子吸收特征与光源的变化强度或“基线”。当测量涉及复杂的、广泛吸收的分子或非理想的透射效应（例如标准具）时，基线校正变得特别困难。我们展示了一种技术，消除了需要考虑的激光强度的吸收光谱转换测量的气体样品的透射光谱的时域分子自由感应衰减（m-FID）的修改形式，使用倒谱分析方法开发的音频信号处理。m-FID信号的大部分在时间上与源强度分离并且独立于源强度，并且该部分可以直接与模型拟合以确定样品气体性质，而无需校正光源强度。我们在几个复杂的吸收光谱方案中验证了新方法，并讨论了其局限性。该技术适用于任何吸收光谱仪获得的光谱，并为分析复杂光谱提供了一种快速准确的方法。(C)根据OSA开放获取出版协议的条款，2019年美国光学学会
The accuracy of quantitative absorption spectroscopy depends on correctly distinguishing molecular absorption signatures in a measured transmission spectrum from the varying intensity or 'baseline' of the light source. Baseline correction becomes particularly difficult when the measurement involves complex, broadly absorbing molecules or non-ideal transmission effects such as etalons. We demonstrate a technique that eliminates the need to account for the laser intensity in absorption spectroscopy by converting the measured transmission spectrum of a gas sample to a modified form of the time-domain molecular free induction decay (m-FID) using a cepstral analysis approach developed for audio signal processing. Much of the m-FID signal is temporally separated from and independent of the source intensity, and this portion can be fit directly with a model to determine sample gas properties without correcting for the light source intensity. We validate the new approach in several complex absorption spectroscopy scenarios and discuss its limitations. The technique is applicable to spectra obtained with any absorption spectrometer and provides a fast and accurate approach for analyzing complex spectra. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement