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Bibliographic Details
Main Authors: Nan, Lin, Mancini, Andrea, Weber, Thomas, Seah, Geok Leng, Cortes, Emiliano, Tittl, Andreas, Maier, Stefan A.
Format: Recurso digital
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Published: Zenodo 2025
Online Access:https://doi.org/10.1038/s41566-025-01670-9
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Table of Contents:
  • <p>Quasi-bound states in the continuum (qBICs) achieved through symmetry breaking in photonic metasurfaces are a powerful approach for engineering resonances with high quality factors and tunability. However, miniaturization of these devices is limited as the in-plane unit-cell size typically scales linearly with the resonant wavelength. By contrast, polariton resonators can be deeply subwavelength, offering a promising solution for achieving compact devices. Here we demonstrate that low-loss mid-infrared surface phonon polaritons enable metasurfaces supporting qBICs with unit-cell volumes up to 10<sup>5</sup> times smaller than the free-space volume. Using 100-nm-thick free-standing silicon carbide membranes, we achieve highly confined qBIC states with exceptional robustness against incident-angle variations, a feature unique among qBIC systems. This absence of angular dispersion enables mid-infrared vibrational sensing of thin, weakly absorbing molecular layers using a reflective objective, a method that typically degrades resonance quality in standard qBIC metasurfaces. We introduce surface-phonon-polariton-based qBICs as a platform for ultraconfined nanophotonic systems, advancing the miniaturization of mid-infrared sensors and devices for thermal radiation engineering.</p>