Computational Depth-resolved Imaging and Metrology

In this thesis, we explore the benefits of computational imaging methods in the direction of depth-resolved imaging and rough surface characterization using visible and near-infrared light. More specifically, we start by introducing two existing imaging techniques: OCT and ptychography in Chapter 2, and we lay down the fundamentals of both methods. The rest of the thesis is divided into two parts. The first part aims at depth-resolved imaging, where OCT and ptychography are extended and combined. In Chapter 3, we present a computational OCT system and demonstrate 3D reconstruction with micrometer-scale resolutions. In Chapter 4, we introduce a new optical imaging concept that combines ptychography with OCT, and we demonstrate 3D micrometer-scale resolution with both nanolithographic and biological specimens. In Chapter 5, we work towards 3D ptychography, where simulations are performed on weakly scattering samples. The second part of the thesis investigates computational imaging methods as a metrology tool. In Chapter 6, we show that ptychography can be used as a wavefront sensing tool for beam quality, wavefront and lens aberration characterization. In Chapter 7, we apply computational imaging techniques to study rough surfaces.