Designing Huygens’ Metasurfaces for Anomalous Refraction of THz Beams

Huygens’ metasurfaces (HMSs) can serve as compact and efficient quasi-optical components for the terahertz (THz) range. Here, we apply a precise semi-analytical approach to synthesise an HMS anomalously refracting a normally incident beam in the THz range. The structure is composed of five spatially-modulated impedance sheets deposited on four polypropylene films using contact photolithography. The sheets comprise parallel Al strips with periodic capacitive and inductive loads. Numerical simulations predict the refraction power efficiency of 78%, spuriously scattered power fraction of 8%, and absorbed power fraction of 14%.