Wide angle negative refraction in fishnet metamaterials

Exploiting the strong anisotropy of fishnet structures, wide angle and wide band negative refraction can be achieved. Here, numerical as well as experimental demonstration of negative refraction based on the 31 mode under TM incidence has been shown. The origin of the phenomenon is found in the excitation of high order leaky modes, which appear in periodic structures. These results could be interesting in the design of beam steerers, filters or demultiplexers.