Large-angle beaming from asymmetric nanoslit-corrugation structures

Abstract

The beaming effect in single apertures surrounded by periodic corrugations and the manipulation of beaming directions from such structures has gained considerable attention since discovery. Different materials and structural profiles have been studied in this context but directional beaming at angles larger than 45° has not been achieved. We design and demonstrate nanoslits in a gold film flanked by corrugations, which give rise to beaming angles ranging from 45° to 60°. While the previous designs are based on achieving constructive interference at the aimed beaming angle, our approach complements such constructive interference with destructive interference at 0° and, as a result, enhances the directional beaming effect at angles larger than 45°. The structures are fabricated by electron beam lithography with two consecutive lift-off processes. The experimental far-field intensity distributions agree well with the designs.

A simple Mie-resonator based meta-array with diverse deflection scenarios enabling multifunctional operation at near-infrared

“…However, high-efficiency deflection which would be simultaneously wideband and wide-angle cannot be obtained in single-wave regime of PhCGs [10]. Single-wave deflection can also be obtained by using an epsilon-near-zero (meta)material slab combined with a dielectric grating [12], and a metal grating with subwavelength slit(s) or hole(s) that may support surface plasmons [13], but efficiency remains an issue.…”