Terahertz broadband filter and electromagnetically induced transparency structure with complementary metasurface

Abstract

A broadband terahertz metamaterial filter and its complementary metasurface-electromagnetically induced transparency structure are designed, fabricated and demonstrated. The proposed terahertz broadband filter is a single-layer metal-dielectric metamaterial structure, which is easier to fabricate and control compared with the multi-layer metal-dielectric structures reported before. The 3 dB relative bandwidth of the filter is 27% with the center frequency of 0.405 THz. By changing the metal pattern of the filter into a complementary structure, a polarization independent electromagnetically induced transparency (EIT) structure is formed with the transmission peak appearing at 0.3 THz between the two dips at 0.27 THz and 0.42 THz. The filter and EIT samples have the same dimension in the unit cell, and could be fabricated from the same mask but using different polar photoresist during the photolithographic process. The transmission spectra and physical mechanism of the two complementary structures are investigated based on the superposition theory, surface currents and field distributions. The encouraging results afforded by the filter and the EIT structure could find their applications in broadband terahertz communication systems, terahertz sensors and other emerging THz technologies.

Keywords

• Terahertz
• Metamaterial
• Filter
• Electromagnetically induced transparency