Abstract: Bound states in the continuum (BICs) are ubiquitous in many areas of physics, attracting special interest for their ability to confine waves with infinite lifetimes. Metasurfaces provide a suitable platform to realize them in photonics; such BICs are remarkably robust, being however complex to tune in frequency-wavevector space. Here we propose a scheme to engineer BICs and quasi-BICs with single magnetic-dipole resonance meta-atoms. Upon changing the orientation of the magnetic-dipole resonances, we show that the resulting quasi-BICs, emerging from the symmetry-protected BIC at normal incidence, become transparent for plane-wave illumination exactly at the magnetic-dipole angle, due to a Brewster-like effect. While yielding infinite Q-factors at normal incidence (canonical BIC), these are termed Brewster quasi-BICs since a transmission channel is always allowed that slightly widens resonances at oblique incidences. This is demonstrated experimentally through reflectance measurements in the microwave regime with high-refractive-index mm-disk metasurfaces. Such Brewster-inspired configuration is a plausible scenario to achieve quasi-BICs throughout the electromagnetic spectrum inaccessible through plane-wave illumination at given angles, which could be extrapolated to other kind of waves.
Fuente: Sci Rep 9, 16048 (2019)
Editorial: Nature Publishing Group
Fecha de publicación: 01/11/2019
Nº de páginas: 11
Tipo de publicación: Artículo de Revista
Url de la publicación: https://doi.org/10.1038/s41598-019-52223-4
ABUJETAS, DIEGO R.
ANGELA INMACULADA BARREDA GOMEZ
FERNANDO MORENO GRACIA
SÁENZ, JUAN J.
GEFFRIN, JEAN MICHEL
SÁNCHEZ GIL, JOSÉ A.