High Q -factor terahertz metamaterial based on analog of electromagnetically induced transparency and its sensing characteristics

Abstract

A high Q-factor terahertz metamaterial with analog of electromagnetically induced transparency (EIT) effect is designed. The structural unit is composed of double metal wires parallel to each other and a vertical single metal wire in the middle. The single wire, double wires and composite structures are simulated respectively, and the influence of the position and size of the metal wires on the transmittance and quality factor Q of the composite structure is analyzed. The results show that the EIT-like effect occurs with the horizontal shift of the single metal wire and the transmittance and the Q-factor are changed with the increase of the offset distance. Moreover, different Q-factor can be achieved by adjusting the structure and size. By optimization, when the offset distance is 8 μm, a transparent window with 3 dB bandwidth of approximate 11.56 GHz is obtained near 0.73 THz. The corresponding Q-factor is 63.09 and the transmittance is 0.50. Finally, the sensing characteristics of the resonator is measured, showing excellent sensing performance. The refractive index sensitivity is 60.69 GHz/RIU, and FOM value is 5.25/RIU.