Zero refraction in natural materials and the mechanism of metal superlens
We found that a single negative material has the characteristic of zero refraction in near field, and point out that the mechanism of a metal superlens to image with a resolution exceeding the diffraction limitation is different from that of a perfect lens made of a double negative material. The principle of metal superlens is disclosed. Our numerical results based on the zero refraction characteristic is well in agreement with the experimental results. This work brings new understanding about the single negative materials and will lead to the applications of the superlens in the right direction.