title: Tunable figure of merit for a negative-index metamaterial with a sandwich configuration.
abstract: Metamaterials with a free-standing Ag-SU-8-Ag sandwich configuration, perforated with a periodic array of cross-dipole apertures, are fabricated. The transmittance spectra of both experiment and simulation have indicated the existence of two transmission bands in mid-IR frequencies. The high-frequency transmission peak is the guided mode associated with the surface plasmon polariton (SPP), and its location strongly depends on the arm length of the cross-dipole. The lower-frequency transmission peak is proposed to be the antisymmetric plasmon polariton mode, and its location hardly shifts as the size of the cross-dipole varies. Numerical simulations indicate that, on increasing the arm length of the cross-dipole aperture, the coaction of the electric dipole-like mode and the SPP-associated guided mode results in a better figure of merit.
authors.affiliation: Department of Physics, Nanjing Normal University, Nanjing 210097, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Wang
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Ye
authors.forename: Chao
authors.initials: C
authors.lastname: Zheng
authors.forename: Yao
authors.initials: Y
authors.lastname: Qin
authors.forename: Tie Jun
authors.initials: TJ
authors.lastname: Cui