Polarization-sensitive Fourier-domain Optical Coherence Tomography

Optical Coherence Tomography (OCT) has an important role to investigate the morphological microstructures in biological tissue. It is an emerging, noninvasive, powerful technique to image biological tissues. Compared with conventional time domain OCT (TD-OCT), Fourier-domain OCT (FD-OCT) offers high sensitivity, high dynamic rang and high imaging speed. The most prominent application of OCT is in iatrology where it has proved to be a useful tool for imaging biological tissues. Admittedly, there exists birefringence in tendon, cornea, retina, bone, teeth, nerves, muscle and so on. However, It is a blemish that FD-OCT has no the ability to discriminate such birefringence contrast. This problem can be solved by polarization-sensitive OCT (PS-OCT). Its sensation to birefringence is due to those specimens'sensation to polarized incidence light. It has been demonstrated a powerful technology in discerning birefringence contrast of many tissues.A polarization sensitive Fourier domain optical coherence tomography (PS-FD-OCT) system has been developed to noninvasively map depth-resolved images of Stokes parameters of light backreflected.The PS-FD-OCT system is developed to combine the polarization-sensitive configuration based on the initial FDOCT so as to image in biological tissue. Then the Stokes vector images (I, Q, U and V) and the phase retardation image (δ) were obtained by processing the analytical complex fringe signals from two polarization channels in biological tissue. Moreover, a two-phase shifting method is introduced to eliminate the auto-correlation and zero-phase noises caused by the reflections from various optical interfaces in the tissue.To verify the advantage and effectiveness of our system, porcine tendon,rabbit eyes and other biological tissue experiments are performed.It has been demonstrated that this system makes great sense in birefringence biological tissue and in clinical applications.