High-Q Triple-Mode Quasi-Bound States in the Continuum in an Asymmetric Dielectric Metamaterial

Abstract

Bound states in the continuum (BICs) in metamaterials have attracted much attention due to their high efficiency in field enhancing. Currently, the most BICs driven by metamaterials limit to single mode and the quality-factors (Q-factors) are not high enough. In this paper, we numerically demonstrated the triple-mode symmetry-protected BICs (SP-BICs) in an all-dielectric microtube metamaterial. By moving the hollows transversely and longitudinally in microtubes, three SP-BICs are transformed into high Q-factor quasi-BICs (q-BICs), which are supported by asymmetric toroidal dipole, magnetic dipole and electric hexapolar resonances respectively. The maximum Q-factor of q-BIC reaches 67647, which is an advance. This high Q-factor triple-mode q-BICs in all-dielectric microtube metamaterial has great potential in the applications of sensing, laser generation, and nonlinear optics.

Keywords: Symmetry-protected BICsQuasi-BICHigh Q-factorsDielectric metamaterialsMie resonances Toroidal dipole resonance