Transmission properties of composite metamaterials in the terahertz domain

A periodic array of subwavelength holes in a metal film (i.e. one-layer fishnet structure), an array of split-ring resonators (SRRs) and composite metamaterials (CMMs) combining the two former structures on the same board are fabricated and transmission measurements are performed in the terahertz regime. Anomalous enhanced transmission of metallic subwavelength holes and the magnetic mode of the SRRs are observed in the composite metamaterials. A new plasmon resonance due to the coupling between fishnet wires and SRRs in the CMMs is also observed. Numerical simulations agree well with the experimental spectra and further confirm our results. These findings are expected to have potential applications in designing novel metamaterials.