Artificial plasmonic metamaterial fabricated by micro-stereolithography

Micro-structured materials, which contain engineered sub-wavelength components, can be designed to have positive or negative ε and μ at desired frequency. In this paper, we demonstrate a high pass Terahertz (THz) filter which utilizes the lowered plasma frequency of thin metal wire structures. This high pass filter may have applications in the THz imaging systems. The filter is formed by two-dimensional cubic lattice of thin metal wires. The diameter of the wire is 30 μm, the lattice constant is 120 μm, and the length of the wire is 1mm. Micro-stereolithography technique is applied to fabricate this high aspect ratio cylinders. The reflection property of the filter is characterized by Fourier transform infrared (FTIR) spectroscopy, and a plasma frequency at 0.7 THz is observed, which agrees with the approximate theory.