Transverse modulation instability of copropagating light beams and the bright and dark spatial solitons in nonlinear metamaterials

Abstract

Through using the standard split-step Fourier method, it is found that the transverse modulation instability (MI)can develop when beams copropagate in the positive- and the negative-index region of the metamaterials (MMs) respectively and it is equivalent with the temporal MI in the case of two pulses copropagate in the anomalous and normal dispersion regions of the optical fibers respectively, which is meaning that bright and dark electromagnetic spatial solitons may generate simultaneously. Furthermore, it is confirmed that the bright and dark electromagnetic spatial solitons may even generate simultaneously when beams copropagate in MM, which is a new way to generate spatial soliton pair for there is only leading to the generation of bright or dark spatial solitons in conventional material when two beams copropagate.