Metallic Waveguide Arrays for Metasurface‐Like Control with High Simplicity in Design

Abstract Metallic waveguide arrays, consisting of regularly arranged holes, are proposed for metasurface‐like control of phase, polarization, and amplitude, while the design procedure is greatly simplified. In a sharp contrast to the existing metasurface working principles, the phase delay is dependent on the waveguide dimension perpendicular to the polarization direction, but not on the dimension parallel to the polarization direction. Due to the negligible cross‐polarization effect, the phase can be completely independently controlled for two orthogonally polarized waves with either the same or the different frequencies using one waveguide array. Notably, the analytical relationship between the phase delay and hole dimensions can be presented explicitly, which greatly simplifies the design process to select the waveguide array for a desired phase distribution. Furthermore, the amplitude and polarization can be completely controlled by tuning the dimension and the orientation angle of metal holes. Based on the control over phase, polarization, and amplitude, several control functionalities are theoretically and experimentally demonstrated at the terahertz frequency. A control efficiency of up to 70% is experimentally obtained. The freestanding waveguide array with features of both easy availability and high durability may significantly push forward the development of various photonic devices.