Terahertz electromagnetic response of random-bond metal mesh

A metal mesh shows Drude-like metallic effective permittivity dispersion. By cutting all wires of the mesh, the metal mesh becomes a metal cross array and shows Lorentz-like effective permittivity dispersion. We prepared the samples of metal mesh with random cut systematically and measured the transmission spectra in the terahertz region. The spectra show a characteristic change from metallic to insulating ones through the percolation limit.