Dual-modes electromagnetically induced transparency based on carbon nanotube films terahertz metasurface

Electromagnetically induced transparency (EIT) plays an important role in sensors, optical memories, and integrated metamaterials. However, most of the structures can produce only one transparent window, and there are few reports on the application of carbon nanotubes (CNTs) films in EIT. Here, we proposed a terahertz (THz) metasurface based on CNTs, which can produce dual-mode EIT windows. We prepared the CNTs films and extracted the conductivity parameter of the films in the THz region. The EIT transmission spectra have been calculated theoretically by applying the dispersion relation of surface plasmon polariton (SPP) and a three-stage system, which is consistent with the simulation results in each mode. The two EIT windows are tunable as the variation of the incident angles. In addition, the group delays of the two modes reach 16.77 ps and 14.61 ps, respectively. And the group delays are also affected by the incident angles of THz waves. This scheme can further extend to other functional metasurfaces, which offer new methods and platforms for multifunctional THz devices.