Simultaneously Achieving Circular‐To‐Linear Polarization Conversion and Electromagnetically Induced Transparency by Utilizing a Metasurface

Abstract In this work, the simultaneous realization of circular‐to‐linear polarization conversion (PC) and electromagnetically induced transparency (EIT) is theoretically reported in terahertz (THz) range by utilizing a metasurface when left‐handed circularly polarized (LCP) waves are incident. The metasurface is composed of two kinds of via‐coupled modules (VCMs). Each module can realize the same EIT phenomenon by the destructive interference during the bright and dark modes due to the symmetry‐broken rotation operation of the structure instead of the near‐field coupling. The VCMs can simultaneously respond to the incident LCP waves and are identically converted into LCP and right‐handed circularly polarized (RCP) waves, which own the same amplitudes and phase shifts. Therefore, the LCP and RCP waves can generate a resultant linearly polarized (LP) wave. The EIT transparent windows have emerged in 0.729–1.051 THz during the transmission of the LCP waves and the conversion of LCP to RCP. The values of maximum group delays both are 358 ps. The operating frequency band of the PC is located in 0.65–1.10 THz, and relative bandwidth reaches 51.4%. Optimal relative conversion efficiency reaches 93.2% at 0.921 THz. The EIT behavior has been investigated by the two‐oscillator model to further confirm the consistency of the simulation results.