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Mid-Infrared Cross-Comb Spectroscopy

Liu, Mingchen and Gray, Robert M. and Roy, Arkadev and Markus, Charles R. and Marandi, Alireza (2021) Mid-Infrared Cross-Comb Spectroscopy. . (Unpublished)

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Dual-comb spectroscopy has been proven a powerful tool in molecular characterization, which remains challenging to implement in the mid-infrared (MIR) region due to difficulties in the realization of two mutually locked comb sources and efficient photodetection. An effective way to overcome those limitations is optical upconversion; however, previously reported configurations are either demanding or inefficient. Here we introduce and experimentally demonstrate a variant of dual-comb spectroscopy called cross-comb spectroscopy, in which a MIR comb is upconverted via sum-frequency generation (SFG) with a near-infrared (NIR) comb with a shifted repetition rate and then interfered with a spectral extension of the NIR comb. We experimentally demonstrate a proof-of-concept measurement of atmospheric CO₂ around 4.25 micrometer, with a 350-nm instantaneous bandwidth and 25000 resolved comb lines. Cross-comb spectroscopy can be realized using up- or down-conversion and offers an adaptable and efficient alternative to dual-comb spectroscopy outside the well-developed near-IR region, where having two mutually coherent sources and efficient photodetection is challenging. Moreover, the nonlinear gating in cross-comb spectroscopy promises a superior dynamic range compared to dual-comb spectroscopy.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Liu, Mingchen0000-0002-0649-8976
Roy, Arkadev0000-0001-5659-8388
Markus, Charles R.0000-0003-2656-0017
Marandi, Alireza0000-0002-0470-0050
Additional Information:The authors gratefully acknowledge support from AFOSR award FA9550-20-1-0040, NSF Grant No. 1846273, and NASA/JPL. C.R.M. is grateful for support from the Arnold O. Beckman Postdoctoral Fellowship. Author Contributions. The manuscript was written through contributions of all authors. The authors declare no competing interests. Data availability. The data that support the plots within these paper and other findings of this study are available from the corresponding author upon reasonable request. Code availability. The codes used for Fourier transform and spectral linewidth fitting are available from the corresponding author upon reasonable request.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-20-1-0040
Arnold and Mabel Beckman FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:20210825-184628437
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110558
Deposited By: George Porter
Deposited On:30 Aug 2021 17:28
Last Modified:30 Aug 2021 17:28

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