Breakdown of the Kirchhoff’s law of thermal radiation by a spatiotemporally modulated nonreciprocal metasurface

Breakdown of the Kirchhoff’s law of thermal radiation by a spatiotemporally modulated nonreciprocal metasurface | 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 Breakdown of the Kirchhoff’s law of thermal radiation by a spatiotemporally modulated nonreciprocal metasurface Abul Azad, Anatoly Efimov, Chun-Chieh Chang, Simo Pajovic, Wilton Kort-Kamp, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7830542/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 Kirchhoff’s law of thermal radiation, which dictates that the emissivity of a surface equals its absorptivity under thermal equilibrium, fundamentally limits the efficiency of photonic systems by enforcing reciprocal energy exchange between source and detector. Breaking this reciprocity is important for advancing photonic devices for energy conversion, radiative cooling, and mid-infrared sensing and imaging. Driven by the growing need for photonic platforms to overcome reciprocity constraints, we report the first demonstration of spatiotemporally modulated nonreciprocal metasurfaces operating at mid-infrared frequencies enabling the violation of the Kirchhoff’s law at room temperature. We fabricate a graphene-based integrated photonic structure and experimentally demonstrate nonreciprocal reflection from a metasurface modulated at gigahertz frequencies. We further develop a theoretical framework to relate nonreciprocal scattering under spatiotemporal modulation with unequal absorptivity and emissivity for violation of the spectral directional Kirchhoff’s law. Together, our experiment and theory imply effective decoupling of absorption and emission channels by breaking time-reversal symmetry at thermal wavelengths, thereby representing an indirect demonstration of breakdown of Kirchhoff’s law of thermal radiation. Physical sciences/Optics and photonics/Optical materials and structures/Metamaterials Physical sciences/Nanoscience and technology/Nanoscale devices/Nanophotonics and plasmonics Full Text Additional Declarations There is NO Competing Interest. 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. 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-7830542","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":544776336,"identity":"a2b6ea4f-4c39-4b39-b768-2d1e2071935e","order_by":0,"name":"Abul Azad","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAs0lEQVRIiWNgGAWjYLACngoLBgZ20rSckWBgYCZJC28bKVr4248//PB2noS8OTMD84uPbURokTiTkCw5d5uE4c5mBjbLmcRoYTiQcECad5sE44bDDGzGPGeI0CF//mHzb945EvbEazG4kcwmzdsgkQjUwvyYp4IILYY3nrFZzjkmkbzhMGMb4wxitMidT398402Nje2G482HP3wwIEILEmAExQ6JgPkDyVpGwSgYBaNgRAAA6Jkz5woqFE8AAAAASUVORK5CYII=","orcid":"","institution":"Los Alamos National Laboratory","correspondingAuthor":true,"prefix":"","firstName":"Abul","middleName":"","lastName":"Azad","suffix":""},{"id":544776337,"identity":"7e3fd2ed-43e0-4cd5-99b9-6bb36ba917d4","order_by":1,"name":"Anatoly Efimov","email":"","orcid":"","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Anatoly","middleName":"","lastName":"Efimov","suffix":""},{"id":544776338,"identity":"ab10c57e-a4ab-478a-8820-d24d8e9ebdc9","order_by":2,"name":"Chun-Chieh Chang","email":"","orcid":"https://orcid.org/0000-0003-3728-2454","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Chun-Chieh","middleName":"","lastName":"Chang","suffix":""},{"id":544776339,"identity":"53e2e155-83b0-4c2b-9bf5-93c6a061e05f","order_by":3,"name":"Simo Pajovic","email":"","orcid":"","institution":"Massachusetts Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Simo","middleName":"","lastName":"Pajovic","suffix":""},{"id":544776340,"identity":"08c1e4b3-0bca-4b30-a22c-55445e9608b1","order_by":4,"name":"Wilton Kort-Kamp","email":"","orcid":"https://orcid.org/0000-0002-0679-6690","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Wilton","middleName":"","lastName":"Kort-Kamp","suffix":""},{"id":544776341,"identity":"e1123efc-605d-4b8a-bd12-4a7819d02c26","order_by":5,"name":"Dongsung Kim","email":"","orcid":"","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Dongsung","middleName":"","lastName":"Kim","suffix":""},{"id":544776342,"identity":"055bcefd-f6bc-4262-a661-9069ba472b2e","order_by":6,"name":"Hou-Tong Chen","email":"","orcid":"https://orcid.org/0000-0003-2014-7571","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Hou-Tong","middleName":"","lastName":"Chen","suffix":""},{"id":544776343,"identity":"c12f85dd-7017-46ca-8c33-0ec41a799707","order_by":7,"name":"Diego Dalvit","email":"","orcid":"https://orcid.org/0000-0002-5282-2896","institution":"Los Alamos National Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Diego","middleName":"","lastName":"Dalvit","suffix":""}],"badges":[],"createdAt":"2025-10-11 00:35:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7830542/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7830542/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":97669721,"identity":"cf131397-16a6-4c18-941a-35dcf10a1653","added_by":"auto","created_at":"2025-12-08 09:28:46","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1670455,"visible":true,"origin":"","legend":"Article File","description":"","filename":"NatPhotFINALSubmit.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7830542/v1_covered_f0fc9fa2-d8fb-4e7e-8aee-cded1732a833.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Breakdown of the Kirchhoff’s law of thermal radiation by a spatiotemporally modulated nonreciprocal metasurface","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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-7830542/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7830542/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Kirchhoff’s law of thermal radiation, which dictates that the emissivity of a surface equals its absorptivity under thermal equilibrium, fundamentally limits the efficiency of photonic systems by enforcing reciprocal energy exchange between source and detector. Breaking this reciprocity is important for advancing photonic devices for energy conversion, radiative cooling, and mid-infrared sensing and imaging. Driven by the growing need for photonic platforms to overcome reciprocity constraints, we report the first demonstration of spatiotemporally modulated nonreciprocal metasurfaces operating at mid-infrared frequencies enabling the violation of the Kirchhoff’s law at room temperature. We fabricate a graphene-based integrated photonic structure and experimentally demonstrate nonreciprocal reflection from a metasurface modulated at gigahertz frequencies. We further develop a theoretical framework to relate nonreciprocal scattering under spatiotemporal modulation with unequal absorptivity and emissivity for violation of the spectral directional Kirchhoff’s law. Together, our experiment and theory imply effective decoupling of absorption and emission channels by breaking time-reversal symmetry at thermal wavelengths, thereby representing an indirect demonstration of breakdown of Kirchhoff’s law of thermal radiation.","manuscriptTitle":"Breakdown of the Kirchhoff’s law of thermal radiation by a spatiotemporally modulated nonreciprocal metasurface","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-05 05:26:25","doi":"10.21203/rs.3.rs-7830542/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":"5aec72a2-b731-446a-aeb5-bb05b2eb3a47","owner":[],"postedDate":"December 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":57962111,"name":"Physical sciences/Optics and photonics/Optical materials and structures/Metamaterials"},{"id":57962112,"name":"Physical sciences/Nanoscience and technology/Nanoscale devices/Nanophotonics and plasmonics"}],"tags":[],"updatedAt":"2025-12-05T05:26:25+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-05 05:26:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7830542","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7830542","identity":"rs-7830542","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}