ECE PhD Prospectus Defense: Chuan Li

ECE PhD Prospectus Defense: Chuan Li

Title: New strategies for breaking the diffraction limit in optical microscopy

Presenter: Chuan Li

Advisor: Professor Jerome Mertz

Chair: Professor Tianyu Wang

Committee: Professor Jerome Mertz, Professor Lei Tian, Professor Tianyu Wang, Professor Thomas Bifano

Google Scholar Profile: https://scholar.google.com/citations?user=FGUNIfEAAAAJ&hl=en

Abstract: Super-resolution (SR) fluorescence imaging has transformed optical biomicroscopy by enabling resolution beyond the diffraction limit. However, current SR techniques often require multiple raw images, specialized sample preparation, or high photon budgets, limiting their utility for 3D visualization and long-term live sample monitoring.

To address these challenges, we proposed two methods. We first developed multi-plane microscopy with dynamic speckle illumination (DSI). Unlike traditional methods, speckle illumination is a kind of structure illumination with the ability of optical sectioning capability and bringing high-frequency information beyond the diffraction limit into the optical transfer function but robust to aberration, which is suitable for representing a sample in 3D. Using speckle statistics and deblurring techniques, we achieved multi-plane super-resolution imaging in a jellyfish model. However, DSI's dependence on hundreds of images and high photon budget remains a limitation.

To overcome large data acquisition and high photon budget issues, we innovated a variation of laser scanning confocal microscopy (LSCM) system enhanced by single-molecule localization microscopy acquisition principles. This approach surpasses traditional LSCM resolution while maintaining photon efficiency without deconvolution and specialized fluorescence dye. With reassignment operation, our technique ensures aberration robustness and supports extended depth-of-field imaging, enhancing volumetric imaging versatility.

Future work will focus on optimizing the system for large field-of-view, video-rate SR imaging. We will also apply these techniques to biological studies, including neural network regeneration and notch activation analysis, expanding their impact on bioapplications.