Analogue of ultra-broadband and polarization-independent electromagnetically induced transparency using planar metamaterial

In this paper, a classical analogue of electromagnetically induced transparency (EIT) metamaterial is numerically and experimentally demonstrated. The unit cell of our proposed structure is composed of two identical and orthogonal double-end fork (DEF) metallic resonators. Under the excitation of the normally incident waves, each of the two DEFs exhibits different frequency of electric dipole response, which leads to the ultra-broadband and polarization-independent EIT-like effect. The resonant feature of the EIT-like effect has been qualitatively analyzed from the surface current distributions and quantitatively by the “two-oscillator” coupling model. In addition, the large group index is extracted to verify the slow light property within the transmission window. The EIT metamaterial structure with the above-mentioned characteristics may have potential applications in some areas, such as sensing, slow light, and filtering devices.