超常介质中超短电磁脉冲的传输特性研究

将超常介质的色散磁导率合并到非线性极化项中,借鉴常规介质中超短脉冲传输方程的推导方法,得到了非线性超常介质中超短脉冲的传输方程。在德鲁德(Drude)色散模型下,根据脉冲中心频率的不同在传输方程中出现了可正、可负、可为零的自陡峭系数,以及高阶非线性色散项。此外,利用矩方法对传输方程进行分析,得到了超常介质中超短脉冲传输方程的能量守恒定律表达式,揭示了色散磁导率导致的超短脉冲传输的新特性,发现二阶非线性色散使超短脉冲的能量、脉冲频移、脉冲宽度、中心位置和啁啾都随传输距离呈现振荡式变化。

Property of Ultrashort Electromagnetic Pulse Propagation in Metamaterial

By incorporating the dispersive permeability of metamaterial into the nonlinear polarization component,and borrowing the derivation way of nonlinear pulse propagation equation in ordinary material,a general nonlinear propagation equation for ultrashort pulse in metamterial is obtained.It is shown that for Drude dispersive model,the dispersive permeability results in a self-steepening parameter which can be negative,positive or zero depending on the central frequency of the pulse,and a series of high-order nonlinear dispersion terms in the propagation equation.Furthermore,the propagation equation is analyzed by using the moment method,an explicit expression for energy conservation for the propagation equation is obtained,and unique propagation properties of ultrashort pulse in metamaterials are disclosed.It is found that due to the second-order nonlinear dispersion,the characteristic parameters of the ultrashort pulse,including energy,frequency shift,duration,center position,and chirp,all oscillate with propagation distance.