Controlling the polarization through opposite orthogonal transformation with coupling-optimized composite metasurface

Abstract The flexible manipulation of incident polarized waves enhances design freedom for integrated and miniaturized THz devices. This work proposes a method of orthogonal decomposition and transformation to manipulate the polarization of incident fields. It enables symmetric mapping with respect to the S2 axis (x = y) on the Poincaré sphere for any polarized waves. Consequently, arbitrary deflection can be achieved by adjusting the angle between the incident wave and the device. Additionally, the spin will be reversed for circularly and elliptically polarized waves. A specific metasurface is designed to implement this proposal, incorporating a precisely tailored coupling structure to optimize the interaction between cells, which is crucial for maintaining transmittance and bandwidth. All designs are thoroughly validated through numerical simulations. This adaptability and flexibility make it suitable for various applications, including waveplates, polarization convertors and detectors, antennas and radars, etc.