Mid-infrared quantum cascade laser-based structured illumination microscope

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Spectroscopy

Background:

• Mid-infrared (3-20 μm) hyperspectral imaging offers unique molecular contrast for chemical mapping.
• Traditional mid-infrared microscopes face challenges with slow acquisition speeds and high costs.
• Existing methods often lack the speed and cost-effectiveness for widespread adoption.

Purpose of the Study:

• To demonstrate the first implementation of Spatial Frequency Modulated Imaging (SPIFI) in the mid-infrared region.
• To develop a cost-effective and faster hyperspectral imaging technique for mid-infrared microscopy.
• To overcome the limitations of conventional mid-infrared microscopy regarding speed and detector costs.

Main Methods:

• Utilized a Quantum Cascade Laser (QCL) as the light source.
• Employed spatial frequency-encoded structured illumination.
• Integrated a low-cost single-pixel mid-infrared detector for data acquisition in transflection mode.

Main Results:

• Achieved hyperspectral imaging in the mid-infrared with a practical trade-off between speed and complexity.
• Demonstrated acquisition speeds comparable to some QCL-based point-scanning systems.
• Presented preliminary resolution measurements and absorption images of mouse brain coronal sections at 6 and 7 μm.

Conclusions:

• The developed SPIFI microscopy system offers a cost-effective and efficient solution for mid-infrared hyperspectral imaging.
• The technique provides chemically selective contrast and robust image formation.
• The system is suitable for future advancements in high-resolution and compressive imaging applications.