Development of Coherence-Gated and Resolution-Multiplexed Optical Imaging Systems

Abstract

Optical interrogation techniques are particularly well-suited for imaging tissue morphology, biological dynamics, and disease pathogenesis by providing noninvasive access to subcellular-resolution diagnostic information. State-of-the-art spectral domain optical coherence tomography (SDOCT) systems provide real-time optical biopsies of in vivo tissue, and have demonstrated clinical potential, particularly for applications in ophthalmology. Recent advances in microscopy and endoscopy have led to improved resolution and compact optical designs, beyond those of conventional imaging systems. Application of encoded and multiplexed illumination and detection schemes may allow for the development of optical tools that surpass classical imaging limitations. Furthermore, complementary technologies can be combined to create multimodal optical imaging tools with advantages over current-generation systems. In this dissertation, the development of coherence-gated and resolution-multiplexed technologies, aimed towards applications in human vitreoretinal imaging is described. Technology development in coherence-gated systems included increasing the imaging range of SDOCT by removing the complex conjugate artifact, improving acquisition speed using a scanning spectrometer design and a two-dimensional detector array, and hardware and algorithmic implementations that facilitated imaging of Doppler flow. Structured illumination microscopy techniques were applied for resolution enhancement, and a spectrally encoded ophthalmic imaging system was developed for en face confocal fundus imaging through a single-mode fiber. These devices were resolution-multiplexed extensions of existing ophthalmic imaging devices, such as scanning laser ophthalmoscopes (SLO), which demonstrated improved resolution and more compact optical designs as compared to their conventional counterparts.Finally, several multimodal ophthalmic diagnostic tools were developed that combined the advantages of OCT with existing imaging devices. These included a combined SLO-OCT system and a vitreoretinal surgical microscope combined with OCT. These devices allowed for concurrent ophthalmic imaging using complementary modalities for improved visualization and clinical utility.