High-Speed Hyperspectral Imaging for Near Infrared Fluorescence and Environmental Monitoring.

Area of Science:

• Optics and Photonics
• Spectroscopy
• Biomedical Imaging

Background:

• Hyperspectral imaging provides rich spectral and spatial data but is typically slow.
• Near-infrared (NIR) wavelengths (>800 nm) are valuable for tissue imaging and molecular fingerprinting due to tissue transparency and vibrational modes.

Purpose of the Study:

• To develop a fast hyperspectral imaging technique in the NIR spectral range.
• To enable label-free molecular fingerprinting and imaging with high spectral resolution.

Main Methods:

• Demonstration of HyperNIR, a fast hyperspectral NIR imaging method using spectral phasor transformation.
• Utilized a liquid crystal variable retarder (LCVR) for tunable sine- and cosine-filtering, converting optical signals into a 2D spectral (phasor) space.
• Acquired spectral information using only three images, achieving hyperspectral frame rates of 0.2 s⁻¹.

Main Results:

• Distinguished NIR fluorophores with emission peaks <5 nm apart by tuning the LCVR across 900-1600 nm.
• Successfully performed label-free hyperspectral NIR reflectance imaging to identify plastic polymers.
• Demonstrated in vivo monitoring of plant health using the developed technique.

Conclusions:

• HyperNIR offers a significant speed improvement for hyperspectral imaging.
• The technique is versatile, applicable to both fluorescence and reflectance imaging.
• Facilitates straightforward hyperspectral imaging for biomedicine and environmental monitoring.