Impedance Matching Plasmonic Metamaterials to Vacuum

We report on a 100 % transmission in oneand two-dimensional plasmonic metamaterials in the terahertz frequency range. At a specific frequency at which the plasmonic meta material is perfectly impedance matched to vacuum, the metal material becomes essentially invisible. In the case of a two-dimensional array of square holes, perfect impedance matching occurs when the effective dielectric constant becomes –2 for samples with hole coverages larger than 0.19. In a one-dimensional array of slits, transmission becomes 100 % when a symmetric eigenmode is excited and therefore the system becomes effectively impedance-matched.