Deep-subwavelength exceptional point in microwave plasmonic resonators for enhanced sensing

Deep-subwavelength exceptional point in microwave plasmonic resonators for enhanced sensing | 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 Deep-subwavelength exceptional point in microwave plasmonic resonators for enhanced sensing Tie Jun Cui, Tian Shuo Bai, Xuanru Zhang, Wan Zhu Wang, Jingjing Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6920873/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 Exceptional points (EPs) in non-Hermitian electromagnetic (EM) systems have been in the spotlight for decades for their remarkable enhancement effects in wave-matter interactions. Here, we explore EPs in an intermediate EM regime, where the electrical size is in deep-subwavelength scale while the phase retardation governs the modulation. The EP state is realized in a pair of coupled microwave plasmonic resonators, each with an electrical size of 1/50 operating wavelength. The highly confined plasmonic evanescent field, associated with asymmetric excitation dynamics, enables pronounced phase modulation capacity in a deep-subwavelength regime. The combination of non-Hermitian EP effect and deep-subwavelength field concentration leads to a dramatic enhancement in wave-matter interactions. Experimental validation of the EM performance is provided by contactless scatterer detection and nanomole-level glucose sensing. The smallest detectable scatterer size is 1/1600 of the wavelength, and the detection limit for glucose reaches 50 nmol at an operating wavelength of 0.32m. Our results reveal novel modulation mechanisms in the deep-subwavelength intermediate EM regime, providing a deeper understanding of non-Hermitian EM systems. The nanomole-level microwave sensing experiments envision a new and promising route for label-free biomedical sensing. Physical sciences/Optics and photonics/Optical materials and structures/Metamaterials Physical sciences/Optics and photonics/Optical physics/Nanophotonics and plasmonics Deep subwavelength exceptional points frequency splitting sensing spoof localized surface plasmons Full Text Additional Declarations There is no conflict of interest Supplementary Files SupplementaryInformation.pdf Supplementary Information 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. 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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-6920873","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":475544597,"identity":"4086e9ff-8a0e-4b63-90d4-be455e12cfc8","order_by":0,"name":"Tie Jun 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plasmons","lastPublishedDoi":"10.21203/rs.3.rs-6920873/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6920873/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Exceptional points (EPs) in non-Hermitian electromagnetic (EM) systems have been in the spotlight for decades for their remarkable enhancement effects in wave-matter interactions. Here, we explore EPs in an intermediate EM regime, where the electrical size is in deep-subwavelength scale while the phase retardation governs the modulation. The EP state is realized in a pair of coupled microwave plasmonic resonators, each with an electrical size of 1/50 operating wavelength. The highly confined plasmonic evanescent field, associated with asymmetric excitation dynamics, enables pronounced phase modulation capacity in a deep-subwavelength regime. The combination of non-Hermitian EP effect and deep-subwavelength field concentration leads to a dramatic enhancement in wave-matter interactions. Experimental validation of the EM performance is provided by contactless scatterer detection and nanomole-level glucose sensing. The smallest detectable scatterer size is 1/1600 of the wavelength, and the detection limit for glucose reaches 50 nmol at an operating wavelength of 0.32m. Our results reveal novel modulation mechanisms in the deep-subwavelength intermediate EM regime, providing a deeper understanding of non-Hermitian EM systems. 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