Dissertation Defense: Shaobai Li, "Three-Dimensional Imaging Techniques for Biomedical Applications"


1:30 to 4:30 p.m., June 20, 2024



The pursuit of extended depth, higher resolution, and three-dimensional (3D) imaging capabilities has been a driving force in the field of biomedical imaging and clinical applications. By providing detailed volumetric representations of biological structures, 3D imaging modalities offer significant advantages over traditional 2D imaging methods, enabling unprecedented insights into the complex three-dimensional architecture and dynamics of biological systems. Chromatic confocal microscopy and Optical Coherence Tomography (OCT) stand out as two techniques offering high-resolution, non-invasive 3D visualization of living tissues and organisms. Chromatic confocal microscopy utilizes longitudinal chromatic aberration to conduct depth scans, facilitating high-resolution 3D imaging of specimens. On the other hand, OCT, a non-invasive interferometric technique, relies on low-coherence interferometry to capture high-resolution depth images of tissues. OCT provides detailed 3D representations of tissue microstructures, making it a valuable tool in clinical disciplines such as ophthalmology, cardiology, and dermatology.

In this dissertation, we concentrate on Chromatic confocal microscopy and Swept source OCT these two techniques and their applications. We first present two digital scanning chromatic confocal microscopes: DMD-based and MicroLED-based chromatic confocal microscopes that eliminate the need for mechanical scanning. Furthermore, we discuss system enhancements achieved through custom optical design, including the integration of freeform prism pairs and hyperchromatic objectives. These advancements enable higher resolution, extended depth imaging, and multifunctional imaging. In terms of SS-OCT, we demonstrate the development of a multimodal intraoral screening system for oral cancer. This system integrates bright field imaging, autofluorescence imaging, and Swept-source OCT, enabling multi-modalities of intraoral imaging. The optical design, mechanical design, and software architecture of this system are comprehensively discussed. The final integrated system and preliminary results will be presented.