Electromagnetically induced transparency in an integrated metasurface based on bright–dark–bright mode coupling

Based on a bright–dark–bright coupling model, a classical analog of an integrated electromagnetically induced transparency (EIT) metasurface at a microwave frequency band is numerically and experimentally demonstrated. The proposed EIT metasurface structure consists of three perpendicularly connected metallic elements: two split-ring resonators (SRRs) which couple directly with normally incident wave supporting the bright modes, and the I-shaped configuration treated as the dark mode. Due to the dual coupling excitation of the middle I-shaped configuration, two anti-parallel electric dipoles were formed in the upper and lower SRRs, resulting in the destructive interference. In addition, the wide-angle incidence and the different polarization-angle incidence of the proposed metasurface were calculated and studied. The group index is extracted and calculated to verify the slow light property within the transparent window. The research in this work reveals that the scheme based on multi-mode coupling is of referable value for constructing EIT-like metamaterials or high transmission bandpass filters.