Electromagnetically Induced Transparency Analogue in Terahertz Range with All-Dielectric Metasurface

An analogue of electromagnetically induced transparency (EIT) in terahertz range with an all-dielectric metasurface is investigated numerically. The unit cell of the silicon-based metasurface is composed of a ring and a rectangular bar. It is found that due to the interaction between the dark mode and the bright mode supported by the ring and the bar, respectively, EIT-like resonance can be realized in this structure. By choosing proper geometrical parameters, the sharp EIT-like transmission peak can be always observed with transmittance higher than 99% and highest Q-factor about 1890. With this high quality EIT resonance, the figure-of-merit for the refractive index sensing of this metasurface is about 260, which is larger the previous reported metal-based metasurfaces. The transmittance property of the EIT-like resonance can be manipulated by changing the structure parameters. This high quality EIT metasurface has great applications in the design of slow-light low-loss equipment, optical modulations, and optical sensing.