Spectral and temporal evidence of robust photonic bound states in the continuum on terahertz metasurfaces

Abstract

DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

Lattice‐Enhanced Fano Resonances from Bound States in the Continuum Metasurfaces

“…This is illustrated by Figure b for normal illumination of PEC ASRR arrays, where the gaps are displaced from the resonator's central vertical axis by the asymmetry parameter d = 0.25 µm (red dashed lines). Both BIC perturbations, either a small illumination angle or a small structural asymmetry, yield QBIC at almost identical spectral positions (Figure b) and similar behavior has also been reported by other groups . Figure also illustrates that the QBIC can be tuned across the broad continuum by changing the coupling distance between the components of the metamaterial unit cell, from high frequencies to an EIT‐like spectrum and low frequencies.…”

“…Both BIC perturbations, either a small illumination angle or a small structural asymmetry, yield QBIC at almost identical spectral positions (Figure 5b) and similar behavior has also been reported by other groups. [22][23][24] Figure 5 also illustrates that the QBIC can be tuned across the broad continuum by changing the coupling distance between the components of the metamaterial unit cell, from high frequencies to an EIT-like spectrum and low frequencies.…”

“…BICs are bound eigenmodes that lie above the photonics light line . This itself is a unique counterintuitive characteristic and because of this, they possess infinite lifetimes and zero‐linewidth resonances under ideal conditions . However, in the real world, ideal conditions are not possible, and therefore the investigation of a quasi‐BIC (QBIC) is the only way to study BIC phenomena.…”

“…[16][17][18][19][20] This itself is a unique counterintuitive characteristic and because of this, they possess infinite lifetimes and zero-linewidth resonances under ideal conditions. [21][22][23][24] However, in the real world, ideal conditions are not possible, and therefore the investigation of a quasi-BIC (QBIC) is the only way to study BIC phenomena. In this context, the QBIC is a point where the symmetry-protected BIC collapses, resulting in loss of its infinite lifetime and zero linewidth.…”

Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

“…BIC was originally proposed by Friedrich and Wintgen in quantum mechanics, and then extended to acoustics, hydrodynamics, and optics [23]. Practically, BIC can be realized as quasi-BIC by introducing the structural asymmetry in the unit cell structure, where both the Q-factor and the resonance linewidth become finite [24]. It was revealed that dielectric metasurfaces with broken in-plane symmetry of unit cells can support high Q-factor resonance arising from the distortion of symmetry-protected BIC [25].…”