负折射介质中脉冲的非线性传输方程

he propagation of pulse in nonlinear dispersive electromagnetic materials is studied and the corresponding nonlinear propagation equation is deduced from Maxwell equations. Further more, with the use of the Drude dispersive model and the slowly-evolving-wave approximation, the envelope equation which the propagation of pulse in negative refraction-index materials follows is studied. On the basis of this equation, the influence of the variation of the center frequency of the pulse on the group velocity, group velocity dispersion, nonlinear coefficient and self-steep coefficient are also investigated.