An unstabilized femtosecond semiconductor laser for dual-comb spectroscopy of acetylene.

Dual-comb systems based on two optical frequency combs of slightly different line spacing emerge as powerful tools in spectroscopy and interferometry. Semiconductor lasers have a high impact in continuous-wave tunable laser spectroscopy. Hem we demonstrate the first dual-comb interferometer based on a single femtosecond semiconductor laser: a dual-comb modelocked optically pumped external-cavity surface-emitting laser (MIXSEL) ideally suited for a 1 to 10 GHz comb spacing. At a center wavelength of 1.03 mu m (9709 cm(-1)) we measured acetylene gas transmittance with a resolution of 2.7 GHz in 100 ms with residual errors of less than 3% using thousand comb lines without aliasing effects. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement