High-speed, wide-field, fiber-based PS-OCT system with real-time surface Stokes feedback for circular input...

Area of Science:

• Biomedical Optics
• Medical Imaging
• Optical Coherence Tomography

Background:

• Fiber-based polarization-sensitive optical coherence tomography (PS-OCT) systems face challenges with input state of polarization (SOP) instability, especially in handheld devices.
• Accurate birefringence imaging of tissue requires stable and controlled polarization of light.
• Existing methods may lack the speed and field of view necessary for comprehensive in vivo diagnostics.

Purpose of the Study:

• To present a high-speed, wide-field, fiber-based PS-OCT system for reliable in vivo birefringence imaging.
• To introduce a real-time feedback mechanism for stabilizing the input SOP in fiber-based PS-OCT.
• To demonstrate the system's capability for detailed structural and polarization-resolved imaging of tissue beds.

Main Methods:

• Development of a fiber-based PS-OCT system utilizing a 600 kHz swept-source laser.
• Implementation of a real-time sample surface Stokes vector feedback mechanism to stabilize incident circular polarization.
• System optimization to balance axial resolution (~37.8 μm) and mitigate polarization mode dispersion (PMD) with a 20 nm bandwidth, achieving >200 extinction ratio.
• Phantom studies for repeatability validation and in vivo imaging of the anterior human oral cavity over a 42×42 mm² field of view.

Main Results:

• The real-time SOP feedback mechanism demonstrated high repeatability (median angular standard deviation of 6.52°).
• The system achieved a wide field of view (42×42 mm²) with detailed structural and polarization contrast.
• Simultaneous assessment of enamel orientation, gingival birefringence, and early-stage tissue abnormalities was enabled.

Conclusions:

• The developed high-speed, wide-field PS-OCT system offers a streamlined and robust solution for in vivo birefringence imaging.
• The real-time SOP stabilization technique overcomes inherent fiber-based instabilities.
• This technology facilitates clinical translation for advanced diagnostics in dentistry and soft tissue imaging.