【摘要】 利用一种扩展的双曲函数级数方法求解超常介质中的传输方程,得到了各种不同情形下的暗孤子解,分析了可控自陡效应和二阶非线性色散效应对孤子形成和传输特性的影响.结果表明,超常介质中负的自陡效应使得暗孤子的中心位置随传输距离向脉冲前沿方向漂移,与常规介质中自陡效应(恒为正)的作用相反;特别是,由于二阶非线性色散的作用,使得在没有线性群速度色散的情形下同样可形成孤子,而且在反常线性色散情形也可形成暗孤子.更多还原

【Abstract】 We use an extended Tanh-function expansion method to solve the nonlinear equation for ultrashort pulse propagation in matamaterial,and obtain dark solitary solutions in various cases.Further,we study the influence of the controllable self-steepening effect and the second-order nonlinear dispersion on the formation and propagation of dark solitons in metamaterials.It is found that the negative self-steepening effect in metamaterial makes the soliton center move to the leading side,opposite to the moving direction of soliton in ordinary materials in which the self-steepening effect is always positive.Most importantly,due to the role of the second-order nonlinear dispersion,dark solitons can be formed in the medium without linear dispersion or with an anomalous linear dispersion.更多还原