Near-field misalignment-robust real-domain Fourier ptychographic microscopy with spherical-wave forward model and micro-LED array illumination

Near-field misalignment-robust real-domain Fourier ptychographic microscopy with spherical-wave forward model and micro-LED array illumination | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Near-field misalignment-robust real-domain Fourier ptychographic microscopy with spherical-wave forward model and micro-LED array illumination Piotr Zdańkowski, Mikolaj Rogalski, Maksymilian Chlipała, Maciej Trusiak, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9198661/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Fourier ptychographic microscopy (FPM) is a computational imaging method that enables high-resolution, large field-of-view quantitative phase imaging of transparent or reflective samples. It conventionally relies on large LED arrays and assumes plane-wave illumination, which constrains system miniaturization and limits performance under near-field illumination conditions. Here, we introduce a compact micro-FPM (μFPM) platform based on near-field illumination from a micro-LED array. It is combined with a new reconstruction framework: a real-domain FPM (rdFPM) algorithm that accurately models spherical wavefront illumination and the improved intensity constraint (IIC) algorithm update procedure, which generally makes any FPM reconstruction robust and stable even in misaligned systems. In the near-field FPM, each micro-LED acts as a localized point source, producing strongly spherical, spatially varying illumination that breaks standard plane-wave FPM models. The proposed rdFPM framework, supported by the designed system-specific calibration method, incorporates spherical wavefront curvature and non-uniform illumination directly into the forward model. Thus, the proposed framework enables robust amplitude and phase reconstruction despite the limited and localized illumination area of individual emitters. Simulations and experimental results using resolution targets target and biological specimens validate the robustness of the proposed μFPM system and rdFPM+IIC reconstruction framework. Results demonstrate high-quality reconstructions of both amplitude and phase objects with 2.5-2.8-fold resolution improvement over the objective diffraction limit, confirming the proposed platform as a compact, alignment-robust, and high-performance alternative to conventional FPM implementations. By uniting on-chip micro-LED illumination with rdFPM+IIC reconstruction and geometry-locked calibration, this work establishes a practical pathway toward true on-chip quantitative Fourier ptychographic microscopy. Physical sciences/Optics and photonics/Optical techniques/Microscopy/Phase-contrast microscopy Physical sciences/Optics and photonics/Optical techniques/Imaging and sensing Full Text Additional Declarations There is no conflict of interest Supplementary Files SuplementFPMuLEDFinal.pdf Supplemental Material Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9198661","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":610562935,"identity":"0dd73b00-0cd9-45b5-8888-d27f74aa3589","order_by":0,"name":"Piotr 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It conventionally relies on large LED arrays and assumes plane-wave illumination, which constrains system miniaturization and limits performance under near-field illumination conditions. Here, we introduce a compact micro-FPM (μFPM) platform based on near-field illumination from a micro-LED array. It is combined with a new reconstruction framework: a real-domain FPM (rdFPM) algorithm that accurately models spherical wavefront illumination and the improved intensity constraint (IIC) algorithm update procedure, which generally makes any FPM reconstruction robust and stable even in misaligned systems. In the near-field FPM, each micro-LED acts as a localized point source, producing strongly spherical, spatially varying illumination that breaks standard plane-wave FPM models. The proposed rdFPM framework, supported by the designed system-specific calibration method, incorporates spherical wavefront curvature and non-uniform illumination directly into the forward model. 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