Orateur
Description
There is an increasing demand for precise molecular spectroscopy, in particular in the mid-IR fingerprint window, whether it be for modelling our atmosphere, interpreting astrophysical spectra or testing fundamental physics. We present a high-resolution mid-IR spectrometer traceable to primary standards providing a unique combination of resolution, tunability, detection sensitivity and frequency control. A 10µm quantum cascade laser (QCL) is phase locked to an optical frequency comb stabilized to a remote 1.5µm ultra-stable reference located at the French national metrological institute. This signal is monitored there on atomic frequency standards and transferred via a noise-compensated fibre link. This results in a ~0.1Hz QCL linewidth, a stability below 10$^{-15}$ from 0.1 to 10s and a frequency uncertainty below 4×10${-14}$ 1. The spectral range covered is ~100GHz, limited by the spectral window of the QCL used and we have demonstrated continuous tunability over a span of ~1 GHz. We have used the apparatus to carry out saturated absorption spectroscopy in compact multipass cells and few-meter-long Fabry-Perot resonators, and demonstrate record sub-10kHz uncertainties on rovibrational frequencies of various species of interest for space and atmospheric physics, and for testing fundamental physics.
1 Argence et al, Nature Photon 9, 456 (2015); Santagata et al, Optica 6, 411 (2019)
| Choix de session parallèle | 1.4 Mesures de précision avec des peignes de fréquence optiques |
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