2-D terahertz metallic photonic crystals in parallel-plate waveguides

Abstract—2-D metallic photonic crystals without defects, with point defects, and with a Fabry–Perot (F–P) defect are character-ized by terahertz time-domain spectroscopy. The metal parallel-plate waveguide (PPWG) with single TEM-mode propagation is used as a tool to simulate 2-D photonic crystals in free space. The 2-D metallic photonic-crystal structures were fabricated by coating Au on an SU-8 polymer cylinder array. Wide terahertz bandgaps were observed in the photonic crystals within the PPWG. The ex-perimental measurements have excellent agreement to 2-D pho-tonic-crystal theory without defects. Defect modes are observed in the samples with defects and show the F–P defect has a strong lo-calization effect. Index Terms—Photonic crystals, submillimeter-wave spec-troscopy, terahertz, waveguides. I