Guiding-mode-assisted double-BICs in an all-dielectric metasurface

Abstract

The electromagnetically induced transparency (EIT) effect realized in a metasurface is potential for slow light applications for its extreme dispersion variation in the transparency window. Herein, we propose an all-dielectric metasurface to generate a double resonance-trapped quasi bound states in the continuum (BICs) in the form of EIT or Fano resonance through selectively exciting the guiding modes with the grating. The group delay of the EIT is effectively improved up to 2113 ps attributing to the ultrahigh Q-factor resonance carried by the resonance-trapped quasi-BIC. The coupled harmonic oscillator model and a full multipole decomposition are utilized to analyze the physical mechanism of EIT-based quasi-BIC. In addition, the BIC based on Fano and EIT resonance can simultaneously exist at different wavelengths. These findings provide a new feasible platform for slow light devices in the near-infrared region.

Switchable strong coupling between dual hyperbolic phonon polaritons and photons in hybrid structure of metasurfaces and h-BN slab

“…It can be clearly observed that guided-mode resonance occurs at resonance wavelength λ = 6.446 μm with the typical standing wave profile. While the incident wave diffracts in the two-dimensional grating, the wave vector can be modulated to match waveguide mode which result in the radiation of waveguide mode and guided-mode resonance can be successfully excited [5,[49][50][51]. In addition, the reflectivity spectrums of uniform h-BN layer are shown in figure 4(c) together with the spectrum got for the metasurfaces with h-BN, where h 1 = 180 nm, h 2 = 250 nm and T = 300 K. The corresponding metasurfaces resonance at same parameters is shown for comparison.…”

“…Particularly, all-dielectric metasurfaces recently drawn numerous attentions due to low thermal conductivity and dissipation comparing metallic metasurfaces [3,4]. The guided-mode resonance can be excited in all-dielectric metasurfaces, and shows a strong field enhancement [5]. Therefore, all-dielectric metasurfaces could provide an ideal platform for implementing enhanced light-matter interaction.…”

Metallic and All‐Dielectric Metasurfaces Sustaining Displacement‐Mediated Bound States in the Continuum

“…[18] A similar effect emerges for symmetric metasurfaces sustaining BICs at normal incidence when the angle of incidence is tuned. [19] A few studies [20][21][22][23] have been conducted introducing an emerging class of BIC-based metasurfaces that can unlock a finite-Q factor q-BIC resonance by relative displacement tuning while preserving the in-plane inversion symmetry.…”

“…[ 18 ] A similar effect emerges for symmetric metasurfaces sustaining BICs at normal incidence when the angle of incidence is tuned. [ 19 ] A few studies [ 20–23 ] have been conducted introducing an emerging class of BIC‐based metasurfaces that can unlock a finite‐Q factor q‐BIC resonance by relative displacement tuning while preserving the in‐plane inversion symmetry. Another desired aspect of metasurfaces is control over the ratio of their radiative to intrinsic loss rates γ rad / γ int that allows, for instance, for transitions between electromagnetically induced transparency and absorption.…”

The impact of contact and contactless interactions between the meta-atoms on terahertz bound states in the continuum

“…Normally, the quasi-BIC is Fano-resonance because a discrete localized state becomes coupled to a continuum of states. In some special cases, the quasi-BIC becomes an electromagnetically induced transparency (EIT) window because of the destructive interference of discrete localized states [24,25], exhibiting a large group delay for slow light application [26,27]. The generation and manipulation of SP-BIC relies on the broken symmetry of the meta-atoms in metasurfaces, which is very well recognized.…”