Coherently-averaged dual comb spectrometer at 7.7 µm with master and follower quantum cascade lasers
| Autor: | Giulio Terrasanta, Thomas Südmeyer, Jérôme Faist, Kenichi Komagata, Stéphane Schilt, Atif Shehzad, Mattias Beck, Renaud Matthey, Andreas Hugi, Lukas Emmenegger, Pierre Brochard, Mehran Shahmohammadi, Valentin J. Wittwer, Filippos Kapsalidis, Michele Gianella, Pierre Jouy |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
Heterodyne business.industry Physics::Optics Beat (acoustics) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Signal Atomic and Molecular Physics and Optics law.invention 010309 optics Injection locking Laser linewidth Optics Orders of magnitude (time) Cascade law 0103 physical sciences 0210 nano-technology business Quantum cascade laser |
| Zdroj: | Optics express. 29(12) |
| ISSN: | 1094-4087 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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