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.
© 2009 Optical Society of America
Original Manuscript: June 1, 2009
Revised Manuscript: October 15, 2009
Manuscript Accepted: October 23, 2009
Published: November 12, 2009
Xudong Wang, Yong-Hong Ye, Chao Zheng, Yao Qin, and Tie Jun Cui, "Tunable figure of merit for a negative-index metamaterial with a sandwich configuration," Opt. Lett. 34, 3568-3570 (2009)