Performance Improvement of an Optical Coherence Tomography System by use of an Optical Pupil Slicer

Abstract

Spectral domain optical coherence tomography (SD-OCT) is a dispersed interferometric technology used to obtain tomographic images, typically of tissue for medical applications. OCT is a competing technology with confocal microscopy (CM) and confocal fluorescent microscopy (CFM), which are both used for biopsy imaging for pathology as the gold standard. OCT offers several advantages over CM/CFM: it is able to acquire a full 3D image in a single pass, it requires little or no sample preparation time, and the axial (depth) and lateral (transverse) resolution are not dependent on one another. SD-OCT is limited in imaging depth to a few millimetres due to the quality performance of the spectrograph section of the instrument--that which determines the sensitivity of the SD-OCT system.

In this thesis a design for an SD-OCT system is presented that is suitable for biopsy imaging for pathological studies, i.e. an OCT microscope. The purpose of this system is to provide a fast diagnosis to be made in a surgical environment to reduce the amount of tissue removed from a patient and lower the chance of a returned visit at a later date due to insufficient tissue removal. The secondary purpose of the SD-OCT microscope is to serve as a research testbed system for implementing novel hardware advancements. One such technology, called an optical pupil slicer (OPS), will be implemented in the instrument to improve the depth imaging performance of the SD-OCT system over conventional SD-OCT systems. The OPS is a device that generally improves the performance of a dispersive-type spectrograph by increasing the spectral resolution without a loss in throughput, thereby increasing the sensitivity of the SD-OCT system.