Bifunctional Integration Performed by a Broadband High-Efficiency Spin-Decoupled Metasurface

摘要

Achieving broadband multitasked integration on an ultrathin interface ispivotal to increasing data capacity. However, broadband bifunctional metasurfacesexhibiting high-efficiency and crosstalk-free characteristics are rarelyseen. Here, three broadband spin-decoupled criteria are developed to designthe meta-atoms of high-efficiency bifunctional metasurfaces. Specifically,six dipole-loaded quasi-I-shaped meta-atoms are proposed to satisfy thebroadband spin-decoupled criteria in radio band from 8.6 to 17.8 GHz (about70% bandwidth) with more than 90% efficiency. The metasurface equippedwith the proposed meta-atoms can keep dispersionless phase gradients andcrosstalk-free characteristics in two orthogonal circular polarizations. Thiswork demonstrates the broadband scheme with spin-decoupled bifunctionalmetasurface, yielding two independent broadband multimode vortex beamsin two completely decoupled helicities. Besides, other possible applicationsof the proposed meta-atoms are illustrated from the perspective of the halfwaveplant (polarization control). Accordingly, the other multitasked-typebifunctional metasurface is fabricated to achieve the broadband integrationof two different functionalities: polarization conversion and full-polarizationanomalous refraction. The proposed schemes offer broadband, polarizationmultiplexing,and multitasked-integration routes for complex electromagneticwave manipulations within a subwavelength thickness, which can stimulatethe development of electromagnetic/optical integration devices with broadbandmultiplexing techniques.