Cavity-Enhanced Vernier Spectroscopy with a Chip-Scale Mid-Infrared Frequency Comb
Abstract
Chip-scale optical frequency combs can provide broadband spectroscopy for diagnosing complex organic molecules. They are also promising as miniaturized laser spectrometers in applications ranging from atmospheric chemistry to geological science and the search for extraterrestrial life. While optical cavities are commonly used to boost sensitivity, it is challenging to realize a compact cavity-enhanced comb-based spectrometer. Here, we apply the Vernier technique to free-running operation of an interband cascade laser frequency comb in a simple linear geometry that performs cavity-enhanced chemical sensing. A centimeter-scale high-finesse cavity simultaneously provides selective mode filtering and enhancement of the path length to 30 m. As a proof-of-concept, we sense transient open-path releases of ppm-level difluoroethane with 2 ms temporal resolution over a 1 THz optical bandwidth centered at 3.64 μm. The sub-MHz comb teeth width governs the optical resolution, while the ∼9.7 GHz comb repetition rate determines the optical sampling grid. The minimum detectable absorption reaches 4.3 × 10⁻² at 300 ms.
Additional Information
© 2022 The Authors. Published by American Chemical Society. Received: December 2, 2021. This work was supported by and was in part performed at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with NASA. The research by L.A.S. was supported by an appointment to the NASA Postdoctoral Program at JPL, administered by Universities Space Research Association under a contract with NASA. The NRL authors acknowledge support from the Office of Naval Research (ONR). C.R.M. is grateful for support from the Arnold and Mabel Beckman Foundation through the A. O. Beckman Postdoctoral Fellowship. Funding: National Aeronautics and Space Agency's (NASA) PICASSO Program (106822/811073.02.24.01.85), PDRDF Program; Universities Space Research Association (USRA), NASA Postdoctoral Program (NPP); Office of Naval Research through the U.S. Naval Research Laboratory. The authors declare no competing financial interest.Attached Files
Submitted - 2112.03977.pdf
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Additional details
- Eprint ID
- 113006
- DOI
- 10.1021/acsphotonics.1c01849
- Resolver ID
- CaltechAUTHORS:20220119-233949917
- NASA/JPL/Caltech
- NASA Postdoctoral Program
- Office of Naval Research (ONR)
- Arnold and Mabel Beckman Foundation
- 106822/811073.02.24.01.85
- NASA
- Created
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2022-01-20Created from EPrint's datestamp field
- Updated
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2022-03-23Created from EPrint's last_modified field