Imaging 3D optic axis orientation with multi-angle polarization-sensitive optical coherence tomography

Polarization-sensitive optical coherence tomography (PS-OCT) visualizes biological tissue microstructure by measuring the pathlength difference, amplitude, and polarization of backscattered light, revealing the tissue’s depth-resolved birefringence and optic axis (OA) orientation. The measured polarization effects vary depending on the direction of illumination, and here we extract 3D polarization information using this variation from biological tissue and a polycarbonate phantom for validation. We collected tomograms at multiple imaging angles by tilting samples with a motorized rotation stage from -30° to +30° in 1° increments and aligned the scans with a physics-informed affine model. The data were compared with a simulation of 3D rotation vectors representing the theoretical birefringence and OA orientation, which were used to estimate the true, underlying 3D OA orientation. These results provide a promising basis to develop efficient 3D OA measurement strategies for in vivo imaging.