APL Photonics (Oct 2024)

Mid-infrared hyperspectral microscopy with broadband 1-GHz dual frequency combs

  • Peter Chang,
  • Ragib Ishrak,
  • Nazanin Hoghooghi,
  • Scott Egbert,
  • Daniel Lesko,
  • Stephanie Swartz,
  • Jens Biegert,
  • Gregory B. Rieker,
  • Rohith Reddy,
  • Scott A. Diddams

DOI
https://doi.org/10.1063/5.0225616
Journal volume & issue
Vol. 9, no. 10
pp. 106111 – 106111-9

Abstract

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Mid-infrared microscopy is an important tool for biological analyses, allowing a direct probe of molecular bonds in their low energy landscape. In addition to the label-free extraction of spectroscopic information, the application of broadband sources can provide a third dimension of chemical specificity. However, to enable widespread deployment, mid-infrared microscopy platforms need to be compact and robust while offering high speed, broad bandwidth, and high signal-to-noise ratio. In this study, we experimentally showcase the integration of a broadband, high-repetition-rate dual-comb spectrometer (DCS) in the mid-infrared range with a scanning microscope. We employ a set of 1-GHz mid-infrared frequency combs, demonstrating their capability for high-speed and broadband hyperspectral imaging of polymers and ovarian tissue. The system covers 1000 cm−1 at νc = 2941 cm−1 with 12.86 kHz spectra acquisition rate and 5 µm spatial resolution. Taken together, our experiments and analysis elucidate the trade-off between bandwidth and speed in DCS as it relates to microscopy. This provides a roadmap for the future advancement and application of high-repetition-rate DCS hyperspectral imaging.