Efficient orbital imaging based on ultrafast momentum microscopy and sparsity-driven phase retrieval
| Autor: | M. Düvel, Daniel Steil, David Schmitt, F. J. S. Kappert, M. Keunecke, G. S. M. Jansen, Christina Möller, Stefan Mathias, D. R. Luke, Wiebke Bennecke, Sabine Steil |
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| Rok vydání: | 2020 |
| Předmět: |
Chemical Physics (physics.chem-ph)
Physics Condensed Matter - Materials Science Pixel Resolution (electron density) Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences General Physics and Astronomy 01 natural sciences 010305 fluids & plasmas Momentum Physics - Chemical Physics 0103 physical sciences Femtosecond Noise (video) Tomography 010306 general physics Phase retrieval Ultrashort pulse Algorithm |
| Zdroj: | New Journal of Physics. 22:063012 |
| ISSN: | 1367-2630 |
| DOI: | 10.1088/1367-2630/ab8aae |
| Popis: | We present energy-resolved photoelectron momentum maps for orbital tomography that have been collected with a novel and efficient time-of-flight momentum microscopy setup. This setup is combined with a 0.5 MHz table-top femtosecond extreme-ultraviolet light source, which enables unprecedented speed in data collection and paves the way towards time-resolved orbital imaging experiments in the future. Moreover, we take a significant step forward in the data analysis procedure for orbital imaging, and present a sparsity-driven approach to the required phase retrieval problem, which uses only the number of non-zero pixels in the orbital. Here, no knowledge of the object support is required, and the sparsity number can easily be determined from the measured data. Used in the relaxed averaged alternating reflections algorithm, this sparsity constraint enables fast and reliable phase retrieval for our experimental as well as noise-free and noisy simulated photoelectron momentum map data. |
| Databáze: | OpenAIRE |
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