Quantum cascade laser based hybrid dual comb spectrometer
Authors: Consolino L., Nafa M., De Regis M., Garrasi K., Mezzapesa F.P., Li L., Davies A.G., Linfield E.H., Vitiello M.S., Bartalini S., De Natale P.
Autors Affiliation: CNR-Istituto Nazionale di Ottica and LENS, Via N. Carrara 1, 50019 Sesto Fiorentino (FI), Italy.
NEST, CNR – Istituto Nanoscienze and Scuola NormaleSuperiore, Piazza S. Silvestro 12, 56127 Pisa, Italy.
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK.
ppqSense Srl, Via Gattinella 20, 50013 Campi Bisenzio FI, Italy.
Abstract: Four-wave-mixing-based quantum cascade laser frequency combs (QCL-FC) are a powerfulphotonic tool, driving a recent revolution in major molecularfingerprint regions, i.e. mid- andfar-infrared domains. Their compact and frequency-agile design, together with their highoptical power and spectral purity, promise to deliver an all-in-one source for the mostchallenging spectroscopic applications. Here, we demonstrate a metrological-grade hybriddual comb spectrometer, combining the advantages of a THz QCL-FC with the accuracy andabsolute frequency referencing provided by a free-standing, optically-rectified THz frequencycomb. A proof-of-principle application to methanol molecular transitions is presented. Themulti-heterodyne molecular spectra retrieved provide state-of-the-art results in line-centerdetermination, achieving the same precision as currently available molecular databases. Thedevised setup provides a solid platform for a new generation of THz spectrometers, pavingthe way to more refined and sophisticated systems exploiting full phase control of QCL-FCs,or Doppler-free spectroscopic schemes.
Journal/Review: COMMUNICATIONS PHYSICS
Volume: 3 Pages from: 1 to: 9
KeyWords: Metrology, Terahertz spectroscopy, Comb spectroscopy, Dual-Comb spectroscopy, Spectroscopy, Lasers, Quantum Cascade Lasers, OpticsDOI: 10.1038/s42005-020-0344-0