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An approach is described for spectrally parallel hyperspectral mid-infrared imaging with spatial resolution dictated by fluorescence imaging. Quantum cascade laser (QCL)-based dual-comb mid-infrared spectroscopy enables the acquisition of infrared spectra at high speed (<1 millisecond) through the generation of optical beat patterns and radio-frequency detection. The high-speed nature of the spectral acquisition is shown to support spectral mapping in microscopy measurements. Direct detection of the transmitted infrared beam yields high signal-to-noise spectral information, but long infrared wavelengths impose low diffraction-limited spatial resolution. The use of fluorescence detected photothermal infrared (F-PTIR) imaging provides high spatial resolution tied directly to the integrated IR absorption. Computational imaging using a multi-agent consensus equilibrium (MACE) approach combines the high spatial resolution of F-PTIR and the high spectral information of dual-comb infrared transmission in a single optimized equilibrium hyperspectral data cube.
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This content will become publicly available on August 1, 2026
Application of optical photothermal infrared spectroscopy (O-PTIR) for future returned Mars samples
Optical photothermal infrared spectroscopy (O-PTIR) was used to characterize a terrestrial rock sample as a demonstration of the technique’s enhanced spatial resolution as it corresponds to minerology and the detection of organics. Traditional reflectance-based infrared techniques are limited by the wavelength of the infrared light interacting with the surface along with additional optical dispersion issues. However, because of the nature in which the infrared spectrum is measured via O-PTIR, these traditional issues are eliminated. This is possible through the recent developments of high intensity quantum cascade-based infrared lasers capable of scanning the mid infrared spectrum (3000–500 cm−1). Individual O-PTIR and diffuse reflectance data were collected on a terrestrial rock sample and compared to a recent discovery of NASA JPL’s Perseverance Rover regarding inclusions of comparable size. In addition, an O-PTIR map of a particularly dense area of proteinaceous material in the terrestrial sample was collected, further exemplifying the capability. This technique has significant potential for use regarding future returned Mars samples and in situ planetary surface science when considering the spatial resolution, sensitivity, and negligible sample preparation.
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- Award ID(s):
- 2148727
- PAR ID:
- 10659903
- Publisher / Repository:
- AIP
- Date Published:
- Journal Name:
- Review of Scientific Instruments
- Volume:
- 96
- Issue:
- 8
- ISSN:
- 0034-6748
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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