Taming spatial dispersion in wire metamaterial

Thin wire structures are commonly used as 'metamaterials' for simulating the negative electrical response of a plasma. In this they are only partially successful: transverse modes are convincingly reproduced but problems arise from highly dispersive longitudinal modes which can be excited by externally incident radiation and impair the validity of the simple local plasma model. We show how modified designs can essentially eliminate the longitudinal dispersion and restore the simple local model.