Figure 1.

(a) Schematic diagram of the complementary plasmonic metamaterial. Region I is 0.018 mm-thick metal film supported by a dielectric plate with the thickness of 0.5 mm and dielectric constant of 3.38. Region II includes complementary symmetric grooves machined into the metal film. Four different shapes of grooves are considered: T₁-shape (a₂ > a₁), R-shape (a₂ = a₁), T₂-shape (a₂ = 0), and V-shape (a₂ < a₁). (b) Dispersion relations of fundamental modes for the complementary plasmonic metamaterials with four kinds of groove-shapes and the normal structure with the rectangular groove. For comparison, the dispersion curves of higher modes are also displayed. The parameters are set as d = 5.5 mm, h = 6.5 mm, g = 1 mm, a₁ = 1 mm, and a₂ are chosen as four values (2 mm, 1 mm, 0.5 mm, and 0), respectively, to obtain T₁-, R-, T₂- and V-shaped grooves. The inset illustrates the normal structure with rectangular grooves, whose parameters are the same with the R-shaped groove in the complementary structure.