Correcting spectral baseline fluctuations in dual-comb interferometry

A method to measure and correct for spectral baseline fluctuations in dual-comb interferometry is presented. Fluctuations can be measured from the amplitude of beat notes between combs and a continuous wave laser or from a separate measurement of the combs' repetition rates, filtered around the spectral region of interest. Amplitude-dependent spectral variations are characterized using low-resolution Fourier transforms around the centerburst of several interferograms, and a nonstationary filter is applied to properly account for the combs' variations during the measurement. This allows removal of this source of statistical, as well as systematic, errors. (C) 2022 Optical Society of America

Automated summary

This article presents a method to measure and correct for spectral baseline fluctuations in dual-comb interferometry. Fluctuations can be measured by comparing the beat note amplitudes between combs or by separately measuring the repetition rates of the combs and filtering them in the spectral region of interest. Amplitude-dependent spectral variations are characterized using low-resolution Fourier transforms of several interferograms, and a nonstationary filter is applied to properly account for the combs' variations during the measurement, allowing for the removal of statistical and systematic errors.