Effect of phase mismatch on second-harmonic generation in negative-index materials

Second-harmonic generation in negative-index metamaterials is considered. Theoretical analysis of the corresponding model demonstrates a significant difference of this phenomenon in conventional and negative-index materials. For example, and in contrast to conventional materials, there is nonzero critical phase mismatch. The behavior of interacting waves is dramatically different when phase mismatch is smaller or greater than a critical value.