Fabrication and characterization of THz plasmonic filter

Terahertz imaging systems have applications for explosives detection, aircraft guidance and landing in zero-visibility weather condition, as well as terrestrial and astronomical remote sensing. These critical applications need a variety of optical elements in the THz frequency, which has yet to be explored. In this paper, we demonstrate a high pass THz filter which utilizes the lowered plasma frequency of thin metal wire structures. The microstereolithography technique is applied to fabricate the 2D lattice of thin metal cylinders. The reflection property of the filter is characterized by FTIR, and the plasma frequency is determined at 0.7 THz, which agrees with the approximate theory.