Tuning the negative electromagnetic response in periodically perforated metal-dielectric-metal structures

Abstract

We fabricate Ag-SU-8-Ag sandwich metamaterials perforated with a periodic array of dipoles. The transmittance spectra of both experiment and modeling have indicated the existence of low- and high-intensity transmission bands in midinfrared frequencies. The position of these transmission bands depend on the dipole length, and lattice structure. The high-intensity transmission bands are due to the excitation of the external surface plasmon plartion (SPP) modes and the localized modes, while the low-intensity transmission bands are from the excitation of the internal SPP modes. The transmittance of the low transmission bands can be increased by decreasing the relative position of the two transmission bands, and the negative electromagnetic response of the metamaterials is also increased. However, if we further decrease the relative position of the two bands, the low transmission band will be merged in the high transmission band, and no negative electromagnetic response can be retrieved.