暗电磁脉冲在耦合型非线性左手材料中的演化

Evolution of Dark Electromagnetic Pulses in Coupled Nonlinear Left-handed Materials

为分析耦合型非线性左手材料中暗电磁脉冲的演化性质,采用分步傅里叶方法编程在Matlab环境中数值模拟,结果表明:一类不同于耦合的非线性Schr d inger方程组暗孤子解的暗电磁脉冲也能够在这种耦合型非线性左手材料中稳定地演化。这类电磁暗脉冲的κ参数决定了它的演化稳定性:这类暗脉冲当深度较小(即参数κ较小)时,能够稳定地在这种耦合型非线性左手材料中传播;而当深度较大(即参数κ较大)时,则出现了脉冲破裂现象从而不能稳定传播;而当给这种不能稳定的且深度较大的暗电磁脉冲加上一个频率微扰时,暗脉冲便不再破裂且能够稳定地在这种耦合型非线性左手材料中传播,但同时又出现了运动速度变慢(快)的现象,这种现象为控制暗电磁脉冲在左手材料中的破裂和运动速度提供了方法。

A one - parameter single - frequency family of dark electromagnetic pulses that can propagate practically without being disturbed is obtained by performing extensive numerical simulations. The dark electromagnetic pulse related close to the solutions of the coupled nonlinear Schrodinger equations in one - dimensional LHMs is stable when parameter is lower and unstable when parameter is higher. With the same simulation conditions, the split dark electromagnetic pulse will become stable again by adding a frequency perturbation to the pulse, simultaneously appears a phenomenon that the velocity of the dark electromagnetic pulse becomes slow （ or fast）. This result provides a method for controlling the dark electromagnetic pulse split and its velocity in the coupled Left - handed Materials.