Polarization-Maintaining Fiber-Based Optical Coherence Tomography And Its Applications

Abstract

Recent advances in Optical Coherence Tomography (OCT) have enabled wide ranges of attractive applications, including characterization of biological tissues, morphological tracking, intravascular imaging, developmental biology and in functional spectroscopic aspects. Neural activity has been studied using optical methods in the past few decades. The use of light to probe neural activity allows outstanding resolution, and the possibility for simultaneous measurement from a range of targeted locations without physical contact with the tissue. Optically detectable signals, such as transient changes with phase and backscattered light intensity, are captured using spectral-domain OCT system. In this dissertation, a fundamental introduction to polarization-maintaining fiber-based OCT system is overviewed with particular emphasis on our research. We have developed polarization-maintaining fiber-based polarization-sensitive OCT systems for various applications. The system is advantageous in that it simultaneously measures the depth-resolved reflectivity, retardance, and axis orientation information. We present the minute Faraday rotations in clear liquids and tissue-mimicking phantoms, and the capability to detect and measure rapid transient structural changes in nerves during activity using spectral-domain OCT with and without exogenous contrast agents. Transient phase changes from backscattered light during action potential propagation show that the scanner can provide high spatiotemporal resolution cross-sectional images of neural activity and the two-dimensional neural functionality will open the possibility for high spatiotemporal functional imaging in a small volume.