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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Coherent diffraction imaging | 4/4 | https://en.wikipedia.org/wiki/Coherent_diffraction_imaging | reference | science, encyclopedia | 2026-05-05T10:03:59.662514+00:00 | kb-cron |
== In situ CDI == Incomplete measurements have been a problem observed across all algorithms in CDI. Since the detector is too sensitive to absorb a particle beam directly, a beamstop or hole must be placed at its center to prevent direct contact (Pham 2020). Furthermore, detectors are often constructed with multiple panels with gaps between them where data again cannot be collected (Pham 2020). Ultimately, these qualities of the detector result in missing data within the diffraction patterns. In situ CDI is a new method of this imaging technology that could increase resistance to incomplete measurements. In situ CDI images a static region and a dynamic region that changes over time as a result of external stimuli (Hung Lo 2018). A series of diffraction patterns are collected over time with interference from the static and dynamic regions (Hung Lo 2018). Because of this interference, the static region acts as a time invariant constraint that phases patterns together in fewer iterations (Hung Lo 2018). Enforcing this static region as a constraint makes in situ CDI more robust to incomplete data and noise interference in the diffraction patterns (Hung Lo 2018). Overall, in situ CDI provides clearer data collection in fewer iterations than other CDI techniques.
== Related techniques == Various techniques for CDI have been developed over the years and utilized to study samples in physics, chemistry, materials, science, nanoscience, geology, and biology (6); this includes, but is not limited to, plane-wave DCI, Bragg CDI, ptychography, reflection CDI, Fresnel CDI, and sparsity CDI. Ptychography builds on CDI by introducing spatial overlap between multiple diffraction patterns, increasing robustness and enabling full-field phase recovery. The conceptual lineage from CDI to ptychography has been formalized in recent reviews. Instead of recording just one coherent diffraction pattern, several – and sometimes hundreds or thousands – of diffraction patterns are recorded from the same object. Each pattern is recorded from a different area of the object, although the areas must partially overlap with one another. Ptychography is only applicable to specimens that can survive irradiation in the illuminating beam for these multiple exposures. However, it has the advantage that a large field of view can be imaged. The extra translational diversity in the data also means the reconstruction procedure can be faster and ambiguities in the solution space are reduced.
== See also == Jianwei (John) Miao – conducted the first experimental demonstration of CDI and contributed to its development into a general computational microscopy framework. Ptychography Diffraction X-ray diffraction computed tomography List of materials analysis methods Nanotechnology Surface physics Synchrotron
== References ==
== Further reading == Miao, Jianwei (2025). "Computational microscopy with coherent diffractive imaging and ptychography". Nature. doi:10.1038/s41586-024-08278-z.
== External links == Ian Robinson X-Ray Studies Group Page Jian-Min (Jim) Zuo Electron Microscopy Group Page