Abstract
•Dual-band EIT with polarization-insensitive characteristic and high transmission.•Dual-band EIT effect and its group delay can be dynamically controlled.•The bright-bright-quasi-dark coupling mode creates the dual-band EIT effect.•The EIT metasurfaces have small electric size and exhibit miniaturization.
A dual-band electromagnetically induced transparency (EIT) effect with high transmission amplitudes and polarization-insensitive characteristic is realized in vanadium dioxide (VO2)-based miniaturized terahertz metasurfaces. The unit cell comprises a metallic spiral (MS) structure, a small square metal frame (SMF2) structure, and a large square metal frame (SMF1) structure. Two transparent windows with the transmission amplitudes of 0.84 and 0.82 are obtained. The surface current distributions reveal that the dual-band EIT effect is created by the bright-bright-quasi-dark coupling mode. The two transparent windows achieve modulation depths of 45.2% and 42.7%, with maximum group delays of 3.24 ps and 3.17 ps, respectively. The proposed EIT metasurfaces exhibit an electric size of only 0.25λ0, which is considerably smaller than that of other dual-band EIT metasurfaces. The present study offers a novel approach to investigating multi-band EIT metasurfaces, with considerable promise for the development of multi-band communication devices.
[Display omitted]