Application of Metamaterials and Meta-Atoms to Terahertz Devices

Abstract

Two dimensional terahertz metamaterials, which are split-ring resonators and closed-ring resonators, are printed on high-resistivity silicon substrates by super-fine ink-jet printing. The printed samples show band-reject responses that are originated from the resonances of the meta-atoms. By loading the metaatoms to photoconductive antennas, optical switching of the spectrum and polarization of terahertz radiation has been demonstrated. The switching is based on the sensitivity of the resonance of a splitring resonator on a photoconductive substrate to a change in the capacitance induced by optical pulse irradiation. The spectral and polarization characteristics of the split-ring resonator-loaded photoconductive antennas are reasonably explained by the coupling between the electric dipole induced by the pump laser and the resonances of the split-ring resonators.