Terahertz Metamaterial with Tunable Window Based on Electromagnetically Induced Transparency (EIT) in Self-asymmetric Resonator

The electromagnetically induced transparency (EIT) metamaterial has been extensively studied and applied in the fields of slow-light devices, light storage and filters, where the bandwidth of transparency window plays a very critical factor. In this paper, a simple and effective EIT model with tunable bandwidth of transparency window, composed of a reconstructed H-shaped metal pattern, is proposed. It is found that the coupling between two bright modes contributes to the EIT effect, giving rise to a narrow transparency window through computational simulation. The significant modulation on the bandwidth of the transparency window can be accomplished via manipulating an arm's length of the H-shaped metal pattern. A maximum resonance bandwidth of 0.95THz for the transparency window in the frequency range of 0.1-3 THz is achieved. Furthermore, the metamaterial is fabricated and measured using a terahertz time-domain spectroscopy (TDS) system and the experimental results show good consistence with the simulations. The proposed EIT metamaterial, with the ability of obtaining tunable transparency window, has potential applications in the fields of filters, sensing, nonlinear optics and so on.