Dual-Band High-Efficiency Transmissive Single Substrate Layer Metasurface with Complex-Amplitude Modulations

Multiwavelength metasurfaces with complex-amplitude modulations have attracted great attention due to their unprecedented abilities for electromagnetic wavefront manipulations. In this work, a novel dual-band high-efficiency transmissive complex-amplitude meta-atom is proposed, which is composed of two identical metallic-patterned layers printed on both sides of a substrate. Each metallic layer is perforated with a double-C-shaped split-ring resonator and a single C-slot resonator, which could achieve efficient cross-polarized conversions of over 80% at two operation frequencies under a circular polarization incidence. In addition, an isolation ring is ingeniously positioned between the two resonators to effectively reduce the mutual coupling. By adjusting the rotation angles of the two resonators, 2π phase modulation and amplitude modulation from a maximum value to zero can be individually realized at both frequencies. As a proof-of-concept demonstration, a dual-band meta-hologram is numerically studied and experimentally verified. This proposed method holds great potential across multifunctional applications such as data storage, information encryption, and virtual reality display.