We show that modulation instability may occur even in the normal group-velocity dispersion regime, or in the case of no group-velocity dispersion in metamaterials with a nonlinear electric polarization. The physical origin of the modulation instability is the additional second-order nonlinear dispersion effect resulted from the combination of the linear dispersive magnetic permeability with the nonlinear electric polarization. Based on the Drude model, a numerical simulation is performed to confirm the theoretical predictions, and a detailed discussion on the role of the second-order nonlinear dispersion effect in modulation instability in both negative-index and positive-index regions of metamaterial is presented.
© 2008 Optical Society of America
Original Manuscript: May 29, 2007
Revised Manuscript: September 10, 2007
Manuscript Accepted: October 27, 2007
Published: November 30, 2007
Yuanjiang Xiang, Shuangchun Wen, Xiaoyu Dai, Zhixiang Tang, Wenhua Su, and Dianyuan Fan, "Modulation instability induced by nonlinear dispersion in nonlinear metamaterials," J. Opt. Soc. Am. B 24, 3058-3063 (2007)