Massively parallel sensing of trace molecules and their isotopologues with broadband subharmonic mid-infrared frequency combs

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Mid-infrared spectroscopy offers supreme sensitivity for the detection of trace gases, solids and liquids based on tell-tale vibrational bands specific to this spectral region. Here, we present a new platform for mid-infrared dual-comb Fourier-transform spectroscopy based on a pair of ultra-broadband subharmonic optical parametric oscillators pumped by two phase-locked thulium-fibre combs. Our system provides fast (7 ms for a single interferogram), moving-parts-free, simultaneous acquisition of 350,000 spectral data points, spaced by a 115 MHz intermodal interval over the 3.1–5.5 µm spectral range. Parallel detection of 22 trace molecular species in a gas mixture, including isotopologues containing isotopes such as 13C, 18O, 17O, 15N, 34S, 33S and deuterium, with part-per-billion sensitivity and sub-Doppler resolution is demonstrated. The technique also features absolute optical frequency referencing to an atomic clock, a high degree of mutual coherence between the two mid-infrared combs with a relative comb-tooth linewidth of 25 mHz, coherent averaging and feasibility for kilohertz-scale spectral resolution.

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Fig. 1: Subharmonic OPOs and their comb-mode structure.
Fig. 2: Mode-resolved DCS spectra.
Fig. 3: DCS spectra of a mixture of gases.
Fig. 4: Spectra of isotopologues detected in a mixture of gases at 3 mbar.
Fig. 5: Spectra of trace molecules in ambient air at 10 mbar.
Fig. 6: Noise and the number of averages.

Change history

  • 01 June 2018

    In the version of this Article originally published, in equation (9), the ‘Δ’ in the first ‘Δfrep’ shouldn’t have been included and, in equation (10), within the brackets, frep and f were the wrong way round. These equations have now been corrected in the online versions.


  1. 1.

    Galli, I. et al. Spectroscopic detection of radiocarbon dioxide at parts-per-quadrillion sensitivity. Optica 3, 385–388 (2016).

  2. 2.

    Udem, T., Holzwarth, R. & Hänsch, T. W. Optical frequency metrology. Nature 416, 233–237 (2002).

  3. 3.

    Schliesser, A., Picqué, N. & Hänsch, T. W. Mid-infrared frequency combs. Nat. Photon. 6, 440–449 (2012).

  4. 4.

    Diddams, S. A., Hollberg, L. & Mbele, V. Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb. Nature 445, 627–630 (2007).

  5. 5.

    Nugent-Glandorf, L. et al. Mid-infrared virtually imaged phased array spectrometer for rapid and broadband trace gas detection. Opt. Lett. 37, 3285–3287 (2012).

  6. 6.

    Fleisher, A. J. et al. Mid-infrared time-resolved frequency comb spectroscopy of transient free radicals. J. Phys. Chem. Lett. 5, 2241–2246 (2015).

  7. 7.

    Foltynowicz, A. et al. Optical frequency comb spectroscopy. Faraday Discuss. 150, 23–31 (2011).

  8. 8.

    Haakestad, M. W., Lamour, T. P., Leindecker, N., Marandi, A. & Vodopyanov, K. L. Intracavity trace molecular detection with a broadband mid-IR frequency comb source. J. Opt. Soc. Am. B 30, 631–640 (2013).

  9. 9.

    Meek, S. A., Poisson, A., Guelachvili, G., Hänsch, T. W. & Picqué, N. Fourier transform spectroscopy around 3 μm with a broad difference frequency comb. Appl. Phys. B 114, 573–578 (2014).

  10. 10.

    Khodabakhsh, A. et al. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3–5.4 μm. Opt. Lett. 41, 2541–2544 (2016).

  11. 11.

    Maslowski, P. et al. Surpassing the path-limited resolution of Fourier-transform spectrometry with frequency combs. Phys. Rev. A 93, 021802(R) (2016).

  12. 12.

    Keilmann, F., Gohle, C. & Holzwarth, R. Time-domain mid-infrared frequency-comb spectrometer. Opt. Lett. 29, 1542–1544 (2004).

  13. 13.

    Schliesser, A., Brehm, M., Keilmann, F. & van der Weide, D. W. Frequency-comb infrared spectrometer for rapid, remote chemical sensing. Opt. Express 13, 9029–9038 (2005).

  14. 14.

    Coddington, I., Newbury, N. & Swann, W. Dual-comb spectroscopy. Optica 3, 414–426 (2016).

  15. 15.

    Coddington, I., Swann, W. C. & Newbury, N. R. Coherent multiheterodyne spectroscopy using stabilized optical frequency combs. Phys. Rev. Lett. 100, 013902 (2008).

  16. 16.

    Coddington, I., Swann, W. C. & Newbury, N. R. Time-domain spectroscopy of molecular free-induction decay in the infrared. Opt. Lett. 35, 1395–1397 (2010).

  17. 17.

    Zolot, A. M. et al. Direct-comb molecular spectroscopy with accurate, resolved comb teeth over 43 THz. Opt. Lett. 37, 638–640 (2012).

  18. 18.

    Bernhardt, B. et al. Mid-infrared dual-comb spectroscopy with 2.4 μm Cr2+:ZnSe femtosecond lasers. Appl. Phys. B 100, 3–8 (2010).

  19. 19.

    Zhang, Z., Gardiner, T. & Reid, D. T. Mid-infrared dual-comb spectroscopy with an optical parametric oscillator. Opt. Lett. 38, 3148–3150 (2013).

  20. 20.

    Cruz, F. C. et al. Mid-infrared optical frequency combs based on difference frequency generation for molecular spectroscopy. Opt. Express 23, 26814–26824 (2015).

  21. 21.

    Jin, Y. W., Cristescu, S. M., Harren, F. J. M. & Mandon, J. Femtosecond optical parametric oscillators toward real-time dual-comb spectroscopy. Appl. Phys. B 119, 65–74 (2015).

  22. 22.

    Zhu, F. et al. Mid-infrared dual frequency comb spectroscopy based on fiber lasers for the detection of methane in ambient air. Laser Phys. Lett. 12, 095701 (2015).

  23. 23.

    Kara, O., Zhang, Z., Gardiner, T. & Reid, D. T. Dual-comb mid-infrared spectroscopy with free-running oscillators and absolute optical calibration from a radio-frequency reference. Opt. Express 25, 16072–16082 (2017).

  24. 24.

    Maser, D. L., Ycas, G., Depetri, W. I., Cruz, F. C. & Diddams, S. A. Coherent frequency combs for spectroscopy across the 3–5 μm region. Appl. Phys. B 123, 142 (2017).

  25. 25.

    Baumann, E. et al. Spectroscopy of the methane ν 3 band with an accurate midinfrared coherent dual-comb spectrometer. Phys. Rev. A 84, 062513 (2011).

  26. 26.

    Villares, G., Hugi, A., Blaser, S. & Faist, J. Dual-comb spectroscopy based on quantum cascade laser frequency combs. Nat. Commun. 5, 5192 (2014).

  27. 27.

    Vodopyanov, K. L., Wong, S. T. & Byer, R. L. Infrared frequency comb methods, arrangements and applications. US patent 8,384,990 (2013).

  28. 28.

    Leindecker, N., Marandi, A., Byer, R. L. & Vodopyanov, K. L. Broadband degenerate OPO for mid-infrared frequency comb generation. Opt. Express 19, 6304–6310 (2011).

  29. 29.

    Marandi, A., Leindecker, N., Pervak, V., Byer, R. L. & Vodopyanov, K. L. Coherence properties of a broadband femtosecond mid-IR optical parametric oscillator operating at degeneracy. Opt. Express 20, 7255–7262 (2012).

  30. 30.

    Smolski, V. O., Yang, H., Gorelov, S. D., Schunemann, P. G. & Vodopyanov, K. L. Coherence properties of a 2.6–7.5-μm frequency comb produced as subharmonic of a Tm-fiber laser. Opt. Lett. 41, 1388–1391 (2016).

  31. 31.

    Lee, K. F. et al. Midinfrared frequency combs from coherent supercontinuum in chalcogenide and optical parametric oscillation. Opt. Lett. 39, 2056–2059 (2014).

  32. 32.

    Lee, K. F. et al. Midinfrared frequency comb from self-stable degenerate GaAs optical parametric oscillator. Opt. Express 23, 26596–26603 (2015).

  33. 33.

    Fermann, M. E. & Hartl, I. Ultrafast fibre lasers. Nat. Photon 7, 868–874 (2013).

  34. 34.

    Roy, J., Deschênes, J.-D., Potvin, S. & Genest, J. Continuous real time correction and averaging for frequency comb interferometry. Opt. Express 20, 21932–21939 (2012).

  35. 35.

    Ideguchi, T., Poisson, A., Guelachvili, G., Picqué, N. & Hänsch, T. W. Adaptive real-time dual-comb spectroscopy. Nat. Commun. 5, 3375 (2014).

  36. 36.

    Coddington, I., Swann, W. C. & Newbury, N. R. Coherent dual-comb spectroscopy at high signal-to-noise ratio. Phys. Rev. A 82, 043817 (2010).

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K.L.V. acknowledges support from the Office of Naval Research (ONR), grant number N00014-15-1-2659 and from the Defense Advanced Research Projects Agency (DARPA), grant number W31P4Q-15-1-0008. Z.E.L. acknowledges support from the National Science Foundation under Graduate Research Fellowship Program, grant number 1144246. We thank J. Jiang and K. Lee for sharing their expertise on the Tm-fibre frequency combs, and N. Newbury and S. Diddams for stimulating discussions.

Author information

A.V.M. and V.O.S. constructed the experimental setup. A.V.M. carried out the measurements and analysed the data. Z.E.L. developed the algorithm for data acquisition and processing. K.L.V. initiated and supervised the project; he also analysed the data and wrote the paper.

Correspondence to K. L. Vodopyanov.

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Muraviev, A.V., Smolski, V.O., Loparo, Z.E. et al. Massively parallel sensing of trace molecules and their isotopologues with broadband subharmonic mid-infrared frequency combs. Nature Photon 12, 209–214 (2018) doi:10.1038/s41566-018-0135-2

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