Hyperbolic-enhanced Raman scattering in van der Waals MoOCl2: from Fano resonances to picomolar detection

Hyperbolic-enhanced Raman scattering in van der Waals MoOCl2: from Fano resonances to picomolar detection | 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 Hyperbolic-enhanced Raman scattering in van der Waals MoOCl 2 : from Fano resonances to picomolar detection Valentyn Volkov, Anton Minnekhanov, Gleb Tikhonowski, Georgy Ermolaev, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8367449/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 Natural van der Waals (vdW) crystals with hyperbolic dispersion challenge artificial metamaterials but remain confined to the mid-infrared. The emergence of MoOCl 2 , a quasi-one-dimensional metal with in-plane hyperbolicity, overcomes this spectral limit, shifting the focus to the practical visible range. Here, utilizing angle-resolved Raman spectroscopy, we uncover a highly anisotropic vibrational response characterized by pronounced Fano resonances and polarization switching, which serve as signatures of strong coupling between phonons and the metallic continuum. Harnessing this interaction, we demonstrate “Hyperbolic-Enhanced Raman” (HypER) scattering, where MoOCl 2 provides polarization-tunable enhancement factors exceeding 10 7 and picomolar-level detection down to 100 pM, without any nanostructuring. These results establish MoOCl 2 as a simple, air-stable, wafer-compatible platform for visible-range hyperbolic nanophotonics and lithography-free sensing. Physical sciences/Materials science/Materials for optics/Metamaterials Physical sciences/Optics and photonics/Optical materials and structures van der Waals materials MoOCl2 hyperbolic materials Raman spectroscopy SERS. Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SIMoOCl21.pdf Supporting Information for Hyperbolic-enhanced Raman scattering in van der Waals MoOCl2: from Fano resonances to picomolar detection 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-8367449","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":608819069,"identity":"43cef9d2-3967-4ace-99b8-ef3233421a70","order_by":0,"name":"Valentyn 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