Extraordinary transmission through high accuracy one dimensional periodic structures

We report on the extraordinary transmission through two different one dimensional periodic metallic structures in the terahertz frequency range. The first structure made by fs-lasers with submicron precision has trapezoidal unit cells whereas the second structure consists of circular metallic rods in a row. Localized plasmons lead to highly enhanced transmission at frequencies higher than an effective plasma frequency while surface plasmons give minima in the transmission spectra. The observed Fano profiles are described analytically.