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McKelvey School of Engineering

ESE Seminar: Preliminary Oral Exam Oumeng Zhang

Thursday, December 17, 2020 | 4:00 PM - 6:00 PM

Fluorescence microscopy has been widely utilized to study biochemical processes such as dynamic movements of molecular motors, DNA stretching and unwinding, and compositional changes in lipid membranes. Since the first experimental demonstration of single-molecule localization microscopy (SMLM) with resolution beyond the diffraction limit in 2006, microscopists have developed various techniques to improve the accuracy and precision for measuring not only the 2D position but also the axial position and 3D orientation of SMs. Referring to these methods as SM orientation localization microscopy (SMOLM), I will introduce the operating principles of several widely-used and state-of-the-art SMOLM methods, including the engineered Tri-spot point spread function (PSF) we invented.

With the development of various SMOLM techniques, designing and choosing a method that is optimal for imaging a specific scientific target remain difficult challenges. Although the best-case performances of these methods can be compared using Fisher information and the Cramér-Rao bound (CRB), the best possible accuracy and precision for any imaging system remains unexplored. I will present fundamental accuracy and precision bounds derived using both classical and quantum estimation theory. The conditions need to achieve these performance limits inspire new imaging system designs that are optimal for various experimental scenarios and sample geometries. Interestingly, simple modifications to the standard epifluorescence microscope exhibit better performance in many imaging scenarios compared to complex engineered PSFs. Our analyses suggest future new design paradigms for constructing imaging systems that are superior to existing SMOLM methods.


Event Type



McKelvey School of Engineering


Science & Technology

Electrical & Systems Engineering
Speaker Information

Oumeng Zang
PhD Candidate
Washington University in St. Louis 

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