High-quality trapped modes in all-dielectric metamaterials

A planar all-dielectric metamaterial made of a double-periodic lattice whose unit cell consists of a single subwavelength dielectric particle having the form of a disk possessing a penetrating hole is considered. The resonant states in the transmitted spectra of the metamaterial are identified considering modes inherent to the individual cylindrical dielectric resonator. A correlation between the asymmetry in the particle's geometry, which arises from the off-centered displacement of the hole and the formation of the Mie-type and trapped modes, is established. The advantages of using a coaxial-sector notch instead of a round hole for the trapped mode excitation are explained.