负折射介质中非线性色散效应对调制不稳定性的影响  

Influence of Nonlinear Dispersion Effects on Modulation Instability in Metamaterials

作　　者：张景贵[1,2] 项元江[2] 章礼富[2] 李勇帆[1] 

机构地区：[1]湖南第一师范学院信息科学与工程系,湖南长沙410205 [2]湖南大学计算机与通信学院微纳光电器件及应用教育部重点实验室,湖南长沙410082

出　　处：《中国激光》2012年第7期169-175,共7页Chinese Journal of Lasers

基　　金：湖南省高校科技创新团队支持计划(湘教通[2010]212号);湖南省科技计划(2010GK3049)资助课题

摘　　要：研究了负折射介质中非线性色散效应对调制不稳定性的影响,揭示了若干新的不稳定性现象。得到了有任意高阶线性与非线性色散效应情形下调制不稳定性增益谱的表达式,结果表明:所有偶次非线性色散不但会影响原来的不稳定性,而且可能会导致新的不稳定性区域;而所有的奇次非线性色散将始终抑制调制不稳定性,且与其符号的正负无关。进一步研究了由色散磁导率所诱导的二阶非线性色散效应对调制不稳定性的影响。研究发现它不但能使在常规介质中不可能出现的调制不稳定性现象也能出现,而且可能会导致在无限带宽的调制频率范围内发生新的不稳定性现象,且其增益值将随调制频率的增大而单调增大。The influence of nonlinear dispersion effects on modulation instability （MI） in nonlinear metamaterials （MMs） is investigated and some new instability phenomena are revealed. Firstly, a general expression for MI gain, taking account of the effects of arbitrary high-order nonlinear dispersions, is derived. It is shown that all even-order nonlinear dispersion not only deforms the original instability regions, but also may lead to the appearance of new instability regions; while all odd-order nonlinear dispersion always suppresses MI irrespective of their signs. Then, the influence of second-order nonlinear dispersion （SND） induced by dispersive magnetic permeability is further analyzed. It is found that SND not only leads to the occurrence of MI inaccessible in ordinary materials, but also opens up a new instability window with an infinite modulation frequency range and the gain value increases monotonically with increasing modulation freouencies.

关 键 词：非线性光学 负折射介质 调制不稳定性 超短脉冲传输 

分 类 号：O437[机械工程—光学工程] O441.4[理学—光学]