Notched terahertz Bowtie metamaterials with strongly enhanced near-field and narrowed resonance linewidth

Enhanced near-field and quality factor of resonance are key issues in plasmonic structures. Here, we demonstrate a kind of notched bowtie metamaterials in the terahertz (THz) regime with narrow linewidth and extremely enhanced near field. The notched bowtie is a variation of common bowtie structure created by introducing symmetric notches on the two sides of the triangular metallic structure. Benefiting from the introduction of notches, the modulation depth of transmittance spectra and near-field enhancement of the notched bowtie arrays were strongly enhanced due to the increase of the structure-derived equivalent inductance. The results demonstrated that near-field enhancement can be increased to above 4000. In addition, the designed structure possesses a narrowed resonance linewidth, and thus an improved quality factor, which could be a promising platform for THz sensing and other potential applications of THz metamaterials.