Centerburst-based baseline reconstruction for high-accuracy normalization in dual-comb spectroscopy

Abstract We propose a practical normalization method for dual-comb spectroscopy (DCS) that reconstructs the baseline spectrum directly from a single interferogram (IGM) by selectively using its centerburst component. By extracting only the centerburst region, where the source spectrum and optical transfer characteristics are strongly encoded, and applying two Fourier transform operations, the baseline spectrum is obtained without reference measurements or model-based functions. Experiments using 12 C 2 H 2 show that the resulting normalized spectra agree well with HITRAN-based calculations, giving a residual standard deviation of 0.015 between the measured and calculated transmittance spectra. Comparisons using the same IGM show that the method surpasses polynomial baseline fitting and achieves accuracy comparable to the modified free-induction-decay method, while greatly reducing computational cost and the need for parameter tuning. Owing to its accuracy, robustness, and minimal processing requirements, the method provides a broadly applicable normalization approach for DCS in laboratory and field environments.