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arXiv · 1901.03122

From Fano resonances to bound states in the continuum in dipole arrays at THz frequencies

Diego R. Abujetas·Niels van Hoof·Stan ter Huurne·Jaime Gómez Rivas·José A. Sánchez-Gil
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Abstract

Fano resonances and bound states in the continuum (BICs) exhibit a rich phenomenology stemming from, respectively, their asymmetric line shapes and infinite quality factors. Here, we show experimentally and theoretically that rod dimer metasurfaces exhibit narrow (high-Q) Fano resonances at THz frequencies. These resonances evolve continuously into a BIC as the rods in each dimer become identical. We demonstrate analytically that this is a universal behavior occurring in arrays of dimers consisting of detuned resonant dipoles. Fano resonances arise as a result of the interference between broad and narrow lattice dipole resonances, with high-Q factors tending to infinity in the detuning parameter space as the narrow lattice resonance becomes a BIC for identical resonant dipoles. Similar configurations can be straightforwardly envisioned throughout the electromagnetic spectrum leading to ultrahigh-Q Fano resonances and BICs of interest in photonics applications such as sensing and lasing.

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Diego R. Abujetas, Niels van Hoof, Stan ter Huurne, Jaime Gómez Rivas, José A. Sánchez-Gil. 2019-01-10. From Fano resonances to bound states in the continuum in dipole arrays at THz frequencies. https://doi.org/10.1364/optica.6.000996

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