Abstract
Quantum cascade laser (QCL) frequency combs are a promising candidate for chemical sensing and biomedical diagnostics1,2,3,4. They are electrically pumped and compact, making them an ideal platform for on-chip integration5. Until now, optical feedback is fatal for frequency comb generation in QCLs6. This property limits the potential for integration. Here, we demonstrate coherent electrical injection locking of the repetition frequency to a stabilized radio-frequency oscillator. We prove that the injection-locked QCL spectrum can be phase-locked, resulting in the generation of a frequency comb. We show that injection locking is not only a versatile tool for all-electrical frequency stabilization, but also mitigates the fatal effect of optical feedback. A prototype self-detected dual-comb set-up consisting only of an injection-locked dual-comb chip, a lens and a mirror demonstrates the enormous potential for on-chip dual-comb spectroscopy. These results pave the way to miniaturized and all-solid-state mid-infrared spectrometers.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Dual-comb optical activity spectroscopy for the analysis of vibrational optical activity induced by external magnetic field
Nature Communications Open Access 16 February 2023
-
Planarized THz quantum cascade lasers for broadband coherent photonics
Light: Science & Applications Open Access 24 December 2022
-
High-quality microresonators in the longwave infrared based on native germanium
Nature Communications Open Access 06 October 2022
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
Rent or buy this article
Get just this article for as long as you need it
$39.95
Prices may be subject to local taxes which are calculated during checkout




Data availability
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
References
Faist, J. et al. Quantum cascade laser. Science 264, 553–556 (1994).
Hugi, A., Villares, G., Blaser, S., Liu, H. C. & Faist, J. Mid-infrared frequency comb based on a quantum cascade laser. Nature 492, 229–233 (2012).
Geiser, M. et al. Single-shot microsecond-resolved spectroscopy of the bacteriorhodopsin photocycle with quantum cascade laser frequency combs. Biophys. J. 114, 173a (2018).
Villares, G., Hugi, A., Blaser, S. & Faist, J. Dual-comb spectroscopy based on quantum-cascade-laser frequency combs. Nat. Commun. 5, 5192 (2014).
Villares, G. et al. On-chip dual-comb based on quantum cascade laser frequency combs. Appl. Phys. Lett. 107, 251104 (2015).
Jouy, P. et al. Dual comb operation of λ ~ 8.2 μm quantum cascade laser frequency comb with 1 W optical power. Appl. Phys. Lett. 111, 141102 (2017).
Udem, T., Holzwarth, R. & Hänsch, T. W. Optical frequency metrology. Nature 416, 233–237 (2002).
Udem, T., Reichert, J., Holzwarth, R. & Hänsch, T. W. Absolute optical frequency measurement of the Cesium D 1 line with a mode-locked laser. Phys. Rev. Lett. 82, 3568–3571 (1999).
Holzwarth, R. et al. Optical frequency synthesizer for precision spectroscopy. Phys. Rev. Lett. 85, 2264–2267 (2000).
Bernhardt, B. et al. Cavity-enhanced dual-comb spectroscopy. Nat. Photon. 4, 55–57 (2009).
Haas, J. & Mizaikoff, B. Advances in mid-infrared spectroscopy for chemical analysis. Annu. Rev. Anal. Chem. 9, 45–68 (2016).
Waclawek, J. P. et al. Quartz-enhanced photoacoustic spectroscopy-based sensor system for sulfur dioxide detection using a CW DFB-QCL. Appl. Phys. B 117, 113–120 (2014).
Friedli, P. et al. Four-wave mixing in a quantum cascade laser amplifier. Appl. Phys. Lett. 102, 222104 (2013).
Faist, J. et al. Quantum cascade laser frequency combs. Nanophotonics 5, 272–291 (2016).
Razavi, B. A study of injection locking and pulling in oscillators. IEEE J. Solid-State Circuit 39, 1415–1424 (2004).
Gellie, P. et al. Injection-locking of terahertz quantum cascade lasers up to 35 GHz using RF amplitude modulation. Opt. Express 18, 20799–20816 (2010).
Barbieri, S. et al. Coherent sampling of active mode-locked terahertz quantum cascade lasers and frequency synthesis. Nat. Photon. 5, 306–313 (2011).
St-Jean, M. R. et al. Injection locking of mid-infrared quantum cascade laser at 14 GHz, by direct microwave modulation. Laser Photon. Rev. 8, 443–449 (2014).
Piccardo, M. et al. Time-dependent population inversion gratings in laser frequency combs. Optica 5, 475–478 (2018).
Kane, D. & Trebino, R. Characterization of arbitrary femtosecond pulses using frequency-resolved optical gating. IEEE J. Quantum Electron. 29, 571–579 (1993).
Iaconis, C. & Walmsley, I. A. Spectral phase interferometry for direct electric-field reconstruction of ultrashort optical pulses. Opt. Lett. 23, 792–794 (1998).
Burghoff, D. et al. Terahertz laser frequency combs. Nat. Photon. 8, 462–467 (2014).
Burghoff, D. et al. Evaluating the coherence and time-domain profile of quantum cascade laser frequency combs. Opt. Express 23, 1190–1202 (2015).
Khurgin, J. B., Dikmelik, Y., Hugi, A. & Faist, J. Coherent frequency combs produced by self frequency modulation in quantum cascade lasers. Appl. Phys. Lett. 104, 081118 (2014).
Mansuripur, T. S. et al. Single-mode instability in standing-wave lasers: the quantum cascade laser as a self-pumped parametric oscillator. Phys. Rev. A 94, 063807 (2016).
Singleton, M., Jouy, P., Beck, M. & Faist, J. Evidence of linear chirp in mid-infrared quantum cascade lasers. Optica 5, 948–953 (2018).
Burghoff, D., Yang, Y. & Hu, Q. Computational multiheterodyne spectroscopy. Sci. Adv. 2, e1601227 (2016).
Schwarz, B. et al. Monolithically integrated mid-infrared lab-on-a-chip using plasmonics and quantum cascade structures. Nat. Commun. 5, 4085 (2014).
Schneider, H. & Liu, H. C. Quantum Well Infrared Photodetectors (Springer-Verlag, Berlin Heidelberg, 2006).
Acknowledgements
This work was supported by the Austrian Science Fund (FWF) in the framework of ‘Building Solids for Function’ (Project W1243), the projects ‘NanoPlas’ (P28914-N27) and ‘NextLite’ (F4909-N23). H.D. acknowledges support by the ESF under project CZ.02.2.69/0.0/0.0/16_027/0008371. A.M.A was supported by projects COMTERA—FFG 849614 and AFOSR FA9550-17-1-0340.
Author information
Authors and Affiliations
Contributions
J.H. and B.S. built up the SWIFTS set-up. J.H. carried out the experiments and wrote the manuscript, with B.S. and A.M.A. providing editorial input. H.D., A.M.A. and G.S. were responsible for MBE growth. B.S. developed the algorithm for the SWIFTS data processing and supervised this work. All authors contributed to analysing the results and commented on the paper.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Supplementary notes and figures.
Rights and permissions
About this article
Cite this article
Hillbrand, J., Andrews, A.M., Detz, H. et al. Coherent injection locking of quantum cascade laser frequency combs. Nature Photon 13, 101–104 (2019). https://doi.org/10.1038/s41566-018-0320-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41566-018-0320-3
This article is cited by
-
Dual-comb optical activity spectroscopy for the analysis of vibrational optical activity induced by external magnetic field
Nature Communications (2023)
-
High-quality microresonators in the longwave infrared based on native germanium
Nature Communications (2022)
-
Towards phase-stabilized Fourier domain mode-locked frequency combs
Communications Physics (2022)
-
Planarized THz quantum cascade lasers for broadband coherent photonics
Light: Science & Applications (2022)
-
Femtosecond pulses from a mid-infrared quantum cascade laser
Nature Photonics (2021)