This paper presents accurate measurements of molecular absorption spectra using wavelength-scanned cavity ring-down spectroscopy (CRDS) based on Fourier transforms. The characteristic frequencies of the periodic ring-down time are extracted after the Fourier transform to recover the absorbance and significantly reduce the noise, especially the troublesome wavelength fluctuations. This method is simpler and has lower noise than conventional swept-cavity continuous-wave CRDS (S-CRDS). The smaller fitting residuals of the measured ${\rm CO}_2$ (${6526.374}\;{{\rm cm}^{ - 1}}$) and CO (${6371.299}\;{{\rm cm}^{ - 1}}$) spectra show that the laser wavelength fluctuation effects are effectively reduced and the spectral SNR is improved. The measured ${\rm N}_2$ and Ar perturbed spectral parameters for ${\rm CO}_2$ are consistent with the S-CRDS method results but with smaller uncertainties.

中文翻译：

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傅里叶滤波，快速波长扫描腔衰荡光谱

本文介绍了基于傅立叶变换的波长扫描腔衰荡光谱（CRDS），可以精确测量分子吸收光谱。在傅立叶变换之后提取周期性衰荡时间的特征频率，以恢复吸光度并显着降低噪声，尤其是麻烦的波长波动。与传统的扫频连续波CRDS（S-CRDS）相比，此方法更简单且噪声更低。测得的$ {\ rm CO} _2 $（$ {6526.374} \; {{\ rm cm} ^ {-1}} $）和CO（$ {6371.299} \ ;; {{\ rm cm } ^ {-1}} $）光谱显示有效降低了激光波长波动的影响，并改善了光谱SNR。实测$ {\ rm CO} _2 $的$ {\ rm N} _2 $和Ar扰动的光谱参数与S-CRDS方法的结果一致，但不确定性较小。