doi:10.1038/s41467-024-53182-9engBylinkin, AndreiCastilla, SebastiánSlipchenko, Tetiana M.Domina, KaterynaCalavalle, FrancescoPusapati, Varun-VarmaAutore, MartaCasanova, FèlixHueso, Luis E.Martín-Moreno, LuisNikitin, Alexey Y.Koppens, Frank H. L.Hillenbrand, RainerOn-chip phonon-enhanced IR near-field detection of molecular vibrationsART-2024-140382Phonon polaritons – quasiparticles formed by strong coupling of infrared (IR) light with lattice vibrations in polar materials – can be utilized for surface-enhanced infrared absorption (SEIRA) spectroscopy and even for vibrational strong coupling with nanoscale amounts of molecules. Here, we introduce and demonstrate a compact on-chip phononic SEIRA spectroscopy platform, which is based on an h-BN/graphene/h-BN heterostructure on top of a metal split-gate creating a p-n junction in graphene. The metal split-gate concentrates the incident light and launches hyperbolic phonon polaritons (HPhPs) in the heterostructure, which serves simultaneously as SEIRA substrate and room-temperature infrared detector. When thin organic layers are deposited directly on top of the heterostructure, we observe a photocurrent encoding the layer’s molecular vibrational fingerprint, which is strongly enhanced compared to that observed in standard far-field absorption spectroscopy. A detailed theoretical analysis supports our results, further predicting an additional sensitivity enhancement as the molecular layers approach deep subwavelength scales. Future on-chip integration of infrared light sources such as quantum cascade lasers or even electrical generation of the HPhPs could lead to fully on-chip phononic SEIRA sensors for molecular and gas sensing.2024http://zaguan.unizar.es/record/14555110.1038/s41467-024-53182-9http://zaguan.unizar.es/record/145551oai:zaguan.unizar.es:145551info:eu-repo/grantAgreement/ES/AEI/CEX2023-001286-Sinfo:eu-repo/grantAgreement/ES/DGA/Q-MADinfo:eu-repo/grantAgreement/EC/H2020/785219 /EU/Graphene Flagship Core Project 2/GrapheneCore2This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 785219 -GrapheneCore2info:eu-repo/grantAgreement/EC/H2020/881603/EU/Graphene Flagship Core Project 3/GrapheneCore3This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 881603-GrapheneCore3info:eu-repo/grantAgreement/ES/MCIU/PID2020-Q1115221GB-C41Nature communications 15 (2024), 8907 [10 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess