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Coherently-averaged dual comb spectrometer at 7.7 µm with master and follower quantum cascade lasers
Auteur(s)
Shehzad, Atif
Terrasanta, Giulio
Gianella, Michele
Jouy, Pierre
Kapsalidis, Filippos
Shahmohammadi Mehran, Mehran
Beck Matthias, Matthias
Faist, Jérôme
Emmenegger, Lukas
Hugi, Andreas
Date de parution
2021-6
In
Optics Express
Vol.
12
No
29
De la page
19126
A la page
19139
Revu par les pairs
1
Résumé
We demonstrate coherent averaging of the multi-heterodyne beat signal between two quantum cascade laser frequency combs in a master-follower configuration. The two combs are mutually locked by acting on the drive current to control their relative offset frequency and by radio-frequency extraction and injection locking of their intermode beat signal to stabilize their mode spacing difference. By implementing an analog common-noise subtraction scheme, a reduction of the linewidth of all heterodyne beat notes by five orders of magnitude is achieved compared to the free-running lasers. We compare stabilization and post-processing corrections in terms of amplitude noise. While they give similar performances in terms of signal-to-noise ratio, real-time processing of the stabilized signal is less demanding in terms of computational power. Lastly, a proof-of-principle spectroscopic measurement was performed, showing the possibility to reduce the amount of data to be processed by three orders of magnitude, compared to the free-running system.
Identifiants
Type de publication
journal article
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