Quantum cascade laser frequency stabilisation at the sub-Hz level

Abstract

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.

References in corpus (8)

• Magneto-optical trapping of a diatomic molecule
• Progress in Atomic Fountains at LNE-SYRTE
• Stability of the proton-to-electron mass ratio
• Long-distance frequency transfer over an urban fiber link using optical phase stabilization
• Ultra-stable laser with average fractional frequency drift rate below $5\times 10^{-19}/\mathrm{s}$
• A widely tunable 10-$\mu$m quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy
• Absorption line shape recovery beyond the detection bandwidth limit: application to the precision spectroscopic measurement of the Boltzmann constant
• HCOOH high resolution spectroscopy in the 9.18$\mu$m region

Cited by in corpus (2)

• Laser spectroscopy of cold molecules
• Mixing properties of room temperature patch-antenna receivers in a mid-infrared (9um) heterodyne system