Terahertz extraordinary optical reflection from parallel-plate waveguide arrays

We theoretically and experimentally study the scattering of p-polarized EM waves from 1D arrays of thin metal plates at THz frequencies. In the simulation results, the reflectance is normally small but extraordinarily high under certain conditions. The resonant conditions correspond to coupled excitations between the surface modes along the array and the cavity modes inside the parallel-plate waveguides formed by the plates. Experimentally, we measure the transmittance of the 1D array, and show good agreement between theory and experiment.