Full-field single-shot measurement of beam self-cleaning dynamics in graded-index multimode fibers

Full-field single-shot measurement of beam self-cleaning dynamics in graded-index multimode fibers | 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 Full-field single-shot measurement of beam self-cleaning dynamics in graded-index multimode fibers Goëry Genty, Jiaqi Li, Piotr Ryczkowksi, Joshua Ruelle, Anas Skalli, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7750730/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Kerr beam self-cleaning in graded-index multimode fibers (GRIN MMFs) is a nonlinear effect that drives the spontaneous transformation of complex multimode beams into smooth bell- shaped spatially-coherent output intensity profiles. Its physical origin links to important areas of physics including self-organization, hydrodynamics and nonlinear wave condensation, and from a practical perspective, Kerr beam self-cleaning holds significant promise for spatio-temporal reshaping and high-power beam delivery. However, there is significant debate about the detailed physics of the process, and the fact that previous experimental studies have been based only on spatial intensity measurements has meant that factors such as spectral dynamics, their coupling to modal evolution, and the coherence of beam self-cleaning remain insufficiently understood. In this work, we address these issues directly through a comprehensive experimental study of Kerr self- cleaning in a GRIN MMF where we explicitly reconstruct the complete complex spatial field in real-time using single-shot off-axis digital holography. This interferometric phase-sensitive approach enables us to explicitly resolve the modal structure of the field as a function of spectral content and injected power. This allows us to show that even small-scale spectral broadening arising from self-phase modulation plays a key role in the energy transfer between modes, resulting in nonlinear spatial filtering and spectrally localized self-cleaning. We also show that the dynamics are fully deterministic and perfectly coherent, following a well-defined nonlinear mode evolution rather than being governed by stochastic effects. Our experimental results and physical interpretation are supported by comprehensive numerical simulations. These findings provide conclusive evidence that self-cleaning arises from deterministic and spectrally selective coherent nonlinear mode interactions rather than condensation-like thermodynamic energy redistribution. Beyond addressing the physical understanding of Kerr beam self-cleaning, our approach also opens a more general path to analyze dynamics in multimode systems spectrally, temporarily and spatially. Our insights also have a significant impact for engineered multimode fiber systems where spectral and modal shaping can be co-optimized for advanced applications in nonlinear optics, coherent beam combining, and spatiotemporal control of structured light. Physical sciences/Optics and photonics/Optical physics/Nonlinear optics Physical sciences/Optics and photonics/Optical physics/Ultrafast photonics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryMaterialSelfCleaning.pdf Supplementary Material Video1.mp4 Spatial intensity vs. distance in the far and near-field integrated over 0.1 nm narrow spectral slice around the pump wavelength Video2.mp4 Output spatial intensity vs wavelength within a 0.1 nm spectral band Video3.mp4 Spatial intensity vs. distance in the far and near-field integrated over the full spectrum Cite Share Download PDF Status: Under Review 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. 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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-7750730","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":526653372,"identity":"11e039ba-2ad3-498a-9174-27005cf0ad8b","order_by":0,"name":"Goëry 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fibers","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7750730/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7750730/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Kerr beam self-cleaning in graded-index multimode fibers (GRIN MMFs) is a nonlinear\r\neffect that drives the spontaneous transformation of complex multimode beams into smooth bell-\r\nshaped spatially-coherent output intensity profiles. Its physical origin links to important areas of\r\nphysics including self-organization, hydrodynamics and nonlinear wave condensation, and from a\r\npractical perspective, Kerr beam self-cleaning holds significant promise for spatio-temporal\r\nreshaping and high-power beam delivery. However, there is significant debate about the detailed\r\nphysics of the process, and the fact that previous experimental studies have been based only on\r\nspatial intensity measurements has meant that factors such as spectral dynamics, their coupling to\r\nmodal evolution, and the coherence of beam self-cleaning remain insufficiently understood. In this\r\nwork, we address these issues directly through a comprehensive experimental study of Kerr self-\r\ncleaning in a GRIN MMF where we explicitly reconstruct the complete complex spatial field in\r\nreal-time using single-shot off-axis digital holography. This interferometric phase-sensitive\r\napproach enables us to explicitly resolve the modal structure of the field as a function of spectral\r\ncontent and injected power. This allows us to show that even small-scale spectral broadening\r\narising from self-phase modulation plays a key role in the energy transfer between modes, resulting\r\nin nonlinear spatial filtering and spectrally localized self-cleaning. We also show that the dynamics\r\nare fully deterministic and perfectly coherent, following a well-defined nonlinear mode evolution\r\nrather than being governed by stochastic effects. Our experimental results and physical\r\ninterpretation are supported by comprehensive numerical simulations. These findings provide\r\nconclusive evidence that self-cleaning arises from deterministic and spectrally selective coherent\r\nnonlinear mode interactions rather than condensation-like thermodynamic energy redistribution.\r\nBeyond addressing the physical understanding of Kerr beam self-cleaning, our approach also\r\nopens a more general path to analyze dynamics in multimode systems spectrally, temporarily and\r\nspatially. Our insights also have a significant impact for engineered multimode fiber systems\r\nwhere spectral and modal shaping can be co-optimized for advanced applications in nonlinear\r\noptics, coherent beam combining, and spatiotemporal control of structured light.","manuscriptTitle":"Full-field single-shot measurement of beam self-cleaning dynamics in\ngraded-index multimode fibers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-30 09:35:43","doi":"10.21203/rs.3.rs-7750730/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"950f39cf-7e96-4b4b-8375-5392680752f3","owner":[],"postedDate":"October 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":55979862,"name":"Physical sciences/Optics and photonics/Optical physics/Nonlinear optics"},{"id":55979863,"name":"Physical sciences/Optics and photonics/Optical physics/Ultrafast photonics"}],"tags":[],"updatedAt":"2025-10-30T09:35:43+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-30 09:35:43","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7750730","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7750730","identity":"rs-7750730","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}