Dual-comb spectroscopy in the Mid-IR for Chemical Kinetic Studies

The project has joined three institutions – namely Politecnico di Milano, University of Laval and King Abdullah University of Science Technology - to the scope of realizing a dual-comb spectrometer with an unprecedented capability to track multiple chemical species in the gas phase with sub-millisecond time resolution. The spectrometer developed is based on Erbium-fiber oscillators at 250 MHz and allows optical spectra as large as 9 THz to be acquired at multi-kHz acquisition rate in the 8-12 mm region. This is being applied to the quantitative testing of gas-phase chemical kinetic models in experiments of fuel pyrolysis and oxidation.

Image caption

Upper panel: experimental spectrum of N₂O acquired at 5.1 kHz (blue) as compared to HITRAN simulations (red). Averaging time: 15 s. Lower panel: residuals of a Voigt profile fitting to the measured spectra. The sub-1% value of residuals shows a high signal-to-noise ratio and an exceptional fidelity of the spectrometer over both horizontal and vertical scale.