Ph.D. Dissertation Defense - Yijun Bao

Event Details

Wednesday, March 27, 2019

1:00pm - 3:00pm

Location: 
Room 102A, MiRC

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Event Details

TitleTheory, Development, and Application of Quantitative Phase Imaging Modalities on Standard Microscope Platforms

Committee:

Dr. Thomas Gaylord, ECE, Chair , Advisor

Dr. Wenshan Cai, ECE

Dr. Gee-Kung Chang, ECE

Dr. Christopher Valenta, ECE

Dr. Martin Short, Math

Dr. Sorin Tibuleac, ADVA Optical Networking

Abstract:

The object of this thesis is to develop and generalize quantitative phase imaging (QPI) methods to enable their more widespread use and their application to new classes of objects. QPI is now being used even more widely in these existing fields as well as in industrial applications such as optical fiber characterization. However, the conventional approach for QPI typically involves expensive custom stand-alone systems. To meet the growing QPI need and to reduce the cost, the Optics Laboratory has developed several new QPI methods that can be implemented on existing standard commercial microscope platforms. Since these methods have some limitations, the present thesis focuses on improving these methods. First, an analytical nonparaxial partially coherent 3D phase optical transfer function (POTF) was derived. Using this analytical nonparaxial 3D POTF, MFPI-PC was generalized to the nonparaxial condition without increasing computational time. In order to make MFPI-PC more suitable for annular illumination, weighted-least-squares MFPI-PC (WLS-MFPI-PC) was developed. The analytical 3D POTF also greatly reduces the computation time needed in POTFR by making the transfer function semi-analytical. The improved MFPI-PC and POTFR have been compared through simulations. In addition, a unified, complete, and consistent description of the use of obliquity factor (OF) and OF modifications in 2D and 3D imaging of thin and thick objects was developed. In 3D QPI, an iterative regularization algorithm has been developed for TDPM, which enables faster measurements. An application of 3D QPI to fiber Bragg grating characterization was proposed by combining digital image processing techniques to overcome the short-period difficulty. Finally, specific future work is proposed, which includes further development of QPI methods as well as more applications.

 

Last revised March 7, 2019