Imaging and sensing applications with polarization sensitive optical coherence tomography

Abstract

Recent development of Optical Coherence Tomography (OCT) has expanded the applications of OCT to various fields, from morphological imaging to functional detection. Polarization-sensitive optical coherence tomography (PS-OCT) provides depth-resolved contrasts of tissue structures. In this dissertation, we presented imaging and sensing applications of polarization-maintaining fiber-based PS-OCT systems. For brain imaging, by transcardially perfusion of titanium dioxide particles into the mouse vascular system, brain blood vessels, after dissection and fixation, can be highlighted by distinguishable optical signals. The segmentation and reconstruction of the vasculature are presented by using a deep learning algorithm. Axonal fiber pathways in the mouse brain are delineated by utilizing the retardance and optic axis orientation contrasts. The future advances of this application involve intriguing applications in studying vascular disorders in animal disease models, such as stroke and cancer, and brain injury. And enhanced resolution and performance PS-OCT systems were developed for imaging applications, which delineated small fiber tracts and cerebellar layers in mouse brain. For sensing applications, gold nanoparticles (GNPs) in lateral flow assays (LFAs) are detected by polarization contrasts of PS-OCT when glycerol is applied onto the paper-based membrane of LFAs. The LFAs with different GNPs concentrations are imaged by PS-OCT. The results indicate that cross-polarization contrast can be used to detect low concentration GNPs at a level that is comparable to the detection limit of other LFA readers. With optimizations and future advances, the PS-OCT based method is promising for highly sensitive applications that include reading LFAs with a point-of-care diagnostic product.