Two-dimensional birefringence imaging in biological tissue using phase and polarization sensitive optical coherence tomography

Polarization sensitive optical coherence tomography (PS-OCT) was used to obtain images of optical birefringence in biological tissues. Through simultaneous detection of two orthogonal polarization states of the signal formed by interference of light backscattered from the biological sample and a mirror in the reference arm of a Michelson interferometer, the optical phase delay between light propagating along the fast and slow axes of birefringence was measured. Simultaneous detection of both polarizations also permits reconstruction of the electro-magnetic wave backscattered from the sample. Inasmuch as any fibrous structure will influence the polarization of light, PS-OCT is a potentially powerful technique in the field of biomedical imaging. It allows rapid non-contact investigation of tissue structural properties through spatially resolved imaging of birefringence.