Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 15 of 15 for “"Ptychography"”.
-
Ptychography for Nonlinear Optical Microscopy
… diffraction measurements. I introduce a novel Ptychography model for the simultaneous reconstruction of the components of the nonlinear optical susceptibility tensor and demonstrate the results of this model using numerically generated measurements from a numerical collagen sample. I …
-
Investigation of Size Specific Fe2O3 nanoparticles: Towards Single Nanoparticle Resolved Spectro-ptychography
Ptychography is a scanning coherent diffraction imaging technique, where an unlimited field of view can be probed with a high spatial resolution. This technique relies on the increased coherent flux from third-generation synchrotron sources to measure the absorption and phase of a sample. Since …
-
High-dimensional, multiplexed, single-shot ptychography for spatiotemporal ultrafast pulse-beam characterization
… a computational imaging technique called Ptychography to ultrafast laser metrology. The culmination of our work is the demonstration of single-pulse, reference-free, full-field spatiotemporal characterization of ultrafast pulse-beams. This thesis also details two precursor techniques: …
-
Angstrom-scale imaging of 2D molecular materials via scanning transmission electron microscopy and ptychography
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-12-01
-
INVESTIGATION OF ADVANCED IMAGE RECONSTRUCTION ALGORITHMS FOR ELECTRON MICROSCOPY
… reconstruction algorithms for tomography and ptychography - two fast growing areas in electron microscopy. Using experimental and simulated data, we examine the limitations of advanced reconstruction algorithms and propose new methods to improve existing methods. Chapter 1 provides an overview …
-
Sampling in Computational Cameras
… learning libraries. Finally we focus on Fourier ptychography, a technique combining aperture synthe- sis and phase retrieval. We build a snapshot ptychography system using a camera array and deep neural estimation, which achieves 6.7ˆ improvement in resolution compared to a single camera. We also …
-
Studying magnetic and 3D atomic structure using 4D scanning transmission electron microscopy
… that this is technically possible using electron ptychography under ideal circumstances, but practical considerations like electron dose and position errors will make it extremely challenging to achieve in reality. Next, we investigate the limits of depth resolution in multislice electron …
-
Studying Electronic Textures with Coherent Lensless Imaging
… found to be ubiquitous in our data, focusing on ptychography, the most commonly used lensless imaging method. Then, I turn to the development of an entirely new single-shot lensless imaging method, randomized probe imaging (RPI). RPI has proven to be reliable and robust across a broad range of …
-
Nanofocusing Refractive X-Ray Lenses
… patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wavefield along the focused beam yields findings about …
-
Physical Designs in Artificial Neural Imaging
… in static and dynamic scenes. In scatter ptychography, we show imaging the secondary scatters reflected by a remote target under coherent illumination can create a synthetic aperture on the scatterer. The reconstruction of the object through phase retrieval algorithms can drastically …
-
Strain in Halide Perovskites: Characterisation, Crystallography, Consequences
… coherent diffraction imaging approach to Bragg ptychography in Chapter 6 allows me to spatially correlate increased tensile strain with red-shifted PL spectra and shorter PL lifetimes in a single crystal of CsPbBr<sub>3</sub> purposely isolated from other possible causes of optoelectronic …
-
Diffraction and Spectroscopy of Marine Calcite Biominerals: Insights into Structure and Geochemistry
Anthropogenic climate change is one of the biggest existential threats to the natural world and the place of humans within it. The key to understanding and shaping the future climate lies in exploring records of climate change through Earth's history. Some of our best records of climate over the …
-
High-bandwidth high-precision robust x-ray microscopy - a control systems approach
In this thesis, a systematic framework for designing control for high-precision positioning stages of Velociprobe X-ray microscope at Advanced Photon Source (APS) at Argonne National Laboratory (ANL) is presented. In particular, our focus is on maintaining a precise position of the optics scanning …