Phase retrieval for object and probe in the optical near-field

Autor*innen

• Anna-Lena Robisch

Parameter

• Lehrbücher
• Universitätslehrbücher

Mehr zum Buch

Lensless, holographic X-ray microscopy is a non-invasive imaging technique that achieves nanometer-scale resolution, requiring a high-quality, coherent wave front. However, focusing X-rays with advanced mirrors introduces figure errors that distort intensity profiles, often overshadowing the holographic image. A common correction method involves dividing the hologram by the flat field intensity profile, but this is only effective when the illumination is focused to a point source. Due to finite spot size, this approach results in a loss of resolution. To address this, a new method is proposed that reconstructs both the object and probe simultaneously from uncorrected holograms before phase retrieval. This technique draws inspiration from established holographic full-field X-ray imaging, utilizing holograms defocused to varying degrees. The concept of longitudinal diversity, arising from changes in propagation distance, is employed to phase the sample's transmission function accurately. The algorithm leverages far-field ptychography, where lateral sample translations yield diverse diffraction patterns, adapting this for the optical near-field. To gather sufficient data for simultaneous reconstruction in amplitude and phase, the sample must be translated in all three spatial dimensions. This approach has been validated through simulations and experiments with coherent visible light and hard X-rays from synchrotron sources, pavin

• Sprache: Englisch
• Erscheinungsdatum: 2016