Terahertz plasmonic high pass filter

Metamaterials, which contain engineered subwavelength microstructures, can be designed to have positive or negative epsilon and mu at desired frequencies. In this letter, we demonstrate a metamaterial which has a "plasmonic'' response to electromagnetic waves in the terahertz (THz) range. The sharp change of reflection and transmission at this plasma frequency makes the structure a high pass filter. The reflection response is characterized by Fourier transform infrared spectroscopy, and a plasma frequency at 0.7 THz is observed, which agrees with the theoretical calculation. The metamaterial is a two-dimensional cubic lattice consisting of thin metal wires, having wire diameter of 30 mum, lattice constant of 120 mum, and wire length of 1 mm. The microstereolithography technique is employed to fabricate the high-aspect-ratio lattice. (C) 2003 American Institute of Physics.