Hyper-spectral imaging with up-converted mid-infrared single-photons

Area of Science:

• Quantum optics
• Spectroscopy
• Biomedical imaging

Background:

• Mid-infrared (MIR) hyperspectral imaging offers molecular specificity for biomedical applications.
• Conventional MIR imaging faces challenges due to high-intensity illumination causing photodamage.
• Lack of efficient, room-temperature MIR single-photon detectors limits adoption of single-photon MIR imaging.

Purpose of the Study:

• To develop a single-photon hyperspectral imaging platform for the MIR spectral range.
• To enable label-free, non-invasive molecular imaging at room temperature.
• To overcome photodamage and detector limitations in MIR imaging.

Main Methods:

• Cavity-enhanced spontaneous parametric down-conversion (SPDC) combined with nonlinear frequency up-conversion.
• Utilizing visible-wavelength silicon single-photon avalanche diodes (Si-SPADs) for MIR detection.
• Employing time gating and intensity correlations to suppress background noise and enhance signal-to-noise ratio.

Main Results:

• Demonstrated MIR spectral imaging in the 2.9-3.6 µm range using cost-effective Si-SPADs.
• Achieved room-temperature, low-noise, high-efficiency operation.
• Successfully performed chemically specific single-photon imaging on biological and polymeric samples.

Conclusions:

• The developed platform enables scalable, quantum-enabled MIR imaging.
• This technology offers a non-invasive alternative to conventional MIR imaging techniques.
• Paves the way for advanced molecular diagnostics, environmental sensing, and biomedical research.