Electromagnetically induced transparency in a strongly coupled orthogonal polarization-insensitive planar terahertz metamaterial

Abstract

We demonstrate experimentally and numerically the electromagnetically induced transparency (EIT) effect in a strongly coupled planar terahertz (THz) metamaterial. The circular-shaped four-arc geometry combined with cross resonators ensures the polarization-insensitive response of the EIT for the orthogonal polarization incident THz. The EIT response can be varied by changing the gap between the arc and cross-shaped resonators. The field profiles indicate a strong coupling between the resonators leading to the EIT effect. In order to understand the underlying physical mechanism, we employed a coupled harmonic oscillator model, which suggests an increase in coupling when the distance between resonators is reduced. THz time-domain spectroscopy of the fabricated samples with the same shape and size of the simulated structures was used to verify the numerical findings. Our study uses a symmetric and easy-to-fabricate planar metasurface that can pave the way for the design and construction of THz photonic components, such as optical switches and slow light devices.