Broadband and wide angle perfect reflection by super periodic cubes metamaterials in terahertz region

Abstract

We present three kinds of broadband terahertz perfect reflectors by using all-dielectric metamaterials. Based on the principle of Mie resonances of resonators with high refractive index, the perfect reflection with wide spectrum and wide angle can be achieved. For the first kind of metamaterial, the common type of reflector with one cube in unit cell is demonstrated. For the second kind of reflector, there are two resonators with different geometric parameters in super periodic unit cell. For the third kind of reflector, there are four resonators with different geometric parameters in super periodic unit cell. Importantly, in order to enhance the response of angle for the perfect reflection, we propose the pyramidal composite microstructure metamaterial to realize the broadband reflection at oblique incidence. For the pyramidal composite reflector with four resonators in one super unit cell, the perfect reflection can be obtained from 0.75THz to 1.15THz with the decreased Fano resonant effect at oblique incidence.