Design of polarization-independent Electromagnetically Induced Transparency structure in terahertz band
Metamaterial Electromagnetically Induced Transparency (EIT) structures have attracted much attention for their significant applications in terahertz rotation sensing, filters, storage and temperature sensing elements. However, most researches on terahertz metamaterial EIT are polarization dependent, which limits their application. In this work, we proposed a terahertz EIT structure with polarization-independence. The unit cell of the structure consists of two layers, the first layer is a square ring with two gaps which can be deposited on the crystal substrate by photolithographic technology. The transmission frequency response characteristics of the structure can be modeled as an infinite array in CST Microwave software. To analyze physical characteristic of the EIT structure, the bright and the dark modes occurring in the structure are investigated based on surface current distributions On the other hand, the influence of the substrate on the transmission frequency and magnitude of the EIT are discussed.