High-resolution frequency-domain second-harmonic optical coherence tomography

Area of Science:

• Biomedical Optics
• Biophotonics
• Optical Coherence Tomography

Background:

• Second-harmonic optical coherence tomography (SH-OCT) is a valuable imaging technique for biological tissues.
• Improving the axial resolution and acquisition speed of SH-OCT is crucial for detailed tissue analysis.

Purpose of the Study:

• To enhance the axial resolution of frequency domain SH-OCT.
• To accelerate image acquisition times for SH-OCT.
• To demonstrate the system's capability in imaging biological tissue microstructures.

Main Methods:

• Utilized continuum generated by a femtosecond Yb fiber laser.
• Implemented frequency domain second-harmonic optical coherence tomography (FD-SH-OCT).
• Applied polarization-resolved imaging techniques.

Main Results:

• Achieved a threefold improvement in axial resolution, reaching 12 micrometers.
• Reduced acquisition time by over two orders of magnitude compared to time-domain SH-OCT.
• Successfully visualized highly organized collagen fibrils in fish scales, pig tendon, and rabbit sclera.

Conclusions:

• The developed FD-SH-OCT system offers significantly improved axial resolution and speed.
• The technique enables detailed visualization of collagenous structures in various biological tissues.
• Polarization-resolved imaging provides further insights into tissue organization.