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

We present a high-speed, wide-field, fiber-based polarization-sensitive optical coherence tomography (PS-OCT) system that enables reliable in vivo birefringence imaging of tissue beds. To address the inherent instability of the input state of polarization (SOP) in single-input fiber systems, particularly in handheld configurations, we introduce a real-time sample surface Stokes vector feedback mechanism that dynamically stabilizes the incident circular polarization prior to scanning. The system integrates a 600 kHz swept-source laser with a relatively narrow 20 nm bandwidth to balance axial resolution (∼37.8 μm in air) and mitigate polarization mode dispersion (PMD), achieving an extinction ratio exceeding 200. Phantom studies validated the repeatability of the SOP feedback strategy, with a median angular standard deviation of 6.52° across repeated local axis measurements. In vivo imaging of the anterior human oral cavity demonstrated detailed structural and polarization-resolved contrasts across a 42 × 42 mm² field of view, enabling simultaneous assessment of enamel orientation, gingival birefringence, and early-stage tissue abnormalities. This approach enables a streamlined and robust PS-OCT operation, facilitating the clinical translation of wide-field polarization-sensitive imaging in dentistry and soft tissue diagnostics.