ABSTRACT High‐performance terahertz (THz) polarization converters are critical for next‐generation systems, yet conventional solutions often suffer from bulkiness or high losses. To address this, we present a numerically designed all‐dielectric metasurface consisting of a single‐layer array of silicon pillars. By leveraging form birefringence and Mie‐resonant responses, the anisotropic geometry enables precise phase retardation control. The device demonstrates robust multifunctionality: it operates as a high‐efficiency half‐wave plate (HWP) at 1.09 THz with a polarization conversion ratio greater than 99%, and as a quarter‐wave plate (QWP) at 0.9 and 1.22 THz. Notably, the metasurface maintains high transmittance (>84%) at all designated frequencies. This simple, single‐layer architecture offers a highly integrated, efficient solution for multifunctional THz photonics.
Xu et al. (Fri,) studied this question.