Depth-of-focus extended multi-contrast imaging by polarization-sensitive optical coherence tomography

A three-dimensional label-free multi-contrast imaging for ex vivo tissue investigation is presented. Computational refocusing is implemented in a Jones-matrix polarization-sensitive optical coherence tomography (PS-OCT) system to overcome the trade-off between imaging depth and lateral resolution. The application of multiple contrast imaging, including intensity, birefringence, and degree-of-polarization uniformity (DOPU), is demonstrated by phantom, porcine muscle, and zebrafish measurements. Extended imaging depth with enhanced lateral resolution over millimeter is achieved. In tissue imaging we find some altered birefringence and DOPU estimation, whose size and alteration are proportional to defocus amount. This biased estimation can be numerically mitigated after applying computational refocusing.