Adaptive dual-comb spectroscopy with free-running lasers and resolved comb lines

A new scheme of real-time dual-comb spectroscopy that only uses free-running femtosecond lasers provides distortion-free Fourier spectra with resolved comb lines across the full spectral span of erbium-doped fiber lasers (>;80 nm centered around 1550 nm) without a posteriori data processing.