Adjustment of terahertz response of a metamaterial by an additional metal strip

Considering the difficulty and complexity in adjusting the terahertz (THz) response of the traditional metamaterials (MMs), we proposed a novel method to adjust the THz response characteristics of MMs. Our MMs possess the same structural and material parameters as those of the traditional three layer ATMs, but differently, an additional metal strip is introduced in the middle dielectric layer. Through changing the position and line width of the additional metal strip, the response frequency and absorption for incident THz wave can be effectively adjusted. Results show that if the additional metal strip moves from near the bottom metal to the surface metal, the response frequency is red shifted. If the additional metal strip is located in the middle of the dielectric layer, the absorption reaches maximum (99.98%). If the width of the additional metal strip is enlarged, the response frequency is red shifted, and the absorption is increased. In addition, if the incident angle is <= 45 degrees, both the central response frequencies of the traditional and novel MMs remain stable, and their absorptions are high. However, if the incident angle is >45 degrees, their central response frequencies blue shift, and their absorptions decrease significantly. According to this novel method, the THz responses of MMs can be effectively adjusted, and the complex process for designing the MM structure can also be thus avoided.