Quantum cascade laser frequency stabilisation at the sub-Hz level

Bérengère Argence (1) , Bruno Chanteau (1) , Olivier Lopez (1) , Daniele Nicolodi (2) , Michel Abgrall (2) , Christian Chardonnet (1) , Christophe Daussy (1) , Benoît Darquié (1) , Yann Le Coq (2) , Anne Amy-Klein (1)

1 MMTF
2 LNE - SYRTE - Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace

Quantum Cascade Lasers (QCL) are increasingly being used to probe the mid-infrared “molecular fingerprint” region. This prompted efforts towards improving their spectral performance, in order to reach ever-higher resolution and precision. Here, we report the stabilisation of a QCL onto an optical frequency comb. We demonstrate a relative stability and accuracy of 2x10-15 and 10-14, respectively. The comb is stabilised to a remote near-infrared ultra-stable laser referenced to frequency primary standards, whose signal is transferred via an optical fibre link. The stability and frequency traceability of our QCL exceed those demonstrated so far by two orders of magnitude. As a demonstration of its capability, we then use it to perform high-resolution molecular spectroscopy. We measure absorption frequencies with an 8x10-13 relative uncertainty. This confirms the potential of this setup for ultra-high precision measurements with molecules, such as our ongoing effort towards testing the parity symmetry by probing chiral species.

Mots clés: QCL; frequency comb; frequency stabilisation; Quantum Physics; Physics - Atomic Physics; Physics - Optics

Domaines: Optique [physics.optics]; Physique Atomique [physics.atom-ph]; Physique Quantique [quant-ph]

Bérengère Argence, Bruno Chanteau, Olivier Lopez, Daniele Nicolodi, Michel Abgrall, et al.. Quantum cascade laser frequency stabilisation at the sub-Hz level. Nature Photonics, 2015, 9 (7), pp.456-460. ⟨10.1038/nphoton.2015.93⟩. ⟨hal-01091617⟩