Publications by authors named "A A Levitan"
Single-shot ptychography is a quantitative phase imaging method wherein overlapping beams of light arranged in a grid pattern simultaneously illuminate a sample, allowing a full ptychographic dataset to be collected in a single shot. It is primarily used at optical wavelengths, but there is interest in using it for x-ray imaging. However, constraints imposed by x-ray optics have limited the resolution achievable to date.
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- The study explores the behavior of rare earth nickelates (RENiO) during a phase transition from metal to insulator, focusing on how electron-lattice interactions lead to bond disproportionation and spin order among nickel and ligand spins.
- Researchers investigated a hypothesis that self-doped ligand holes create local spin moments that couple antiferromagnetically with Ni spins, leading to long-range bond and spin order, specifically in NdNiO thin films.
- Using magnetic resonant X-ray scattering, the study found spiral spin patterns in the material that show an unexpected chiral magnetic configuration, hinting at a possible link between this noncollinear magnetic state and unusual ferroelectric characteristics.
Article Synopsis
- The study uses 11.2 keV X-ray diffraction to observe the crystallization of supercooled liquid hydrogen below its melting point.
- Researchers measured changes in the solid and liquid structures dynamically, allowing them to identify the lowest energy crystal forms and determine densities and temperatures.
- Findings show evidence of Arrhenius-like growth kinetics in the stacking direction during the supercooling process.
Lensless imaging methods that account for partial coherence have become very common in the past decade. However, there are no metrics in use for comparing partially coherent light fields, despite the widespread use of such metrics to compare fully coherent objects and wave fields. Here, we show how reformulating the mean squared error and Fourier ring correlation in terms of quantum state fidelity naturally generalizes them to partially coherent wave fields.
View Article and Find Full Text PDFRandomized probe imaging (RPI) is a single-frame diffractive imaging method that uses highly randomized light to reconstruct the spatial features of a scattering object. The reconstruction process, known as phase retrieval, aims to recover a unique solution for the object without measuring the far-field phase information. Typically, reconstruction is done via time-consuming iterative algorithms.
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