CAJ | 학술논문

基于Drude模型研究了超常介质中的色散磁导率对时空不稳定性(STI)的影响,得到了具有赝五阶非线性效应和自陡效应情形下时空不稳定性增益谱的一般表达式.结果表明,在负折射区.对于自聚焦介质.赝五阶非线性使调制增长的频谱范围和增益值增大.而对于自散焦介质,作用则相反,这与常规介质中的现象不同;在正折射区,赝五阶非线性会抑制自聚焦介质中的时空不稳定性,与常规介质中的现象相同.此外,超常介质中自陡效应可能为负值,但无论自陡效应是正或负,都能抑制时空不稳定性的产生.
기우Drude모형연구료초상개질중적색산자도솔대시공불은정성(STI)적영향,득도료구유안오계비선성효응화자두효응정형하시공불은정성증익보적일반표체식.결과표명,재부절사구.대우자취초개질.안오계비선성사조제증장적빈보범위화증익치증대.이대우자산초개질,작용칙상반,저여상규개질중적현상불동;재정절사구,안오계비선성회억제자취초개질중적시공불은정성,여상규개질중적현상상동.차외,초상개질중자두효응가능위부치,단무론자두효응시정혹부,도능억제시공불은정성적산생.
The influence of dispersive magnetic permeability on spatiotemporal instability(STI)in metamaterials is identified based on the Drude model.In the case of co-existence of cubic nonlinearity.pseudo-fifth-order nonlinearity and self-steepening,a generic expression for instability growth rate is derived.It iS found that in the negative-index region,the pseudo-fifth-order nonlinearity increases the range of spectrum and the gain value of STI for the case of self-focusing material while it do opposite for the case of self-defocusing material,which are different from the results in ordinary materials,in the negative-index region,the pseudo-fifth-order nonlinearity will suppress the emergence of STI for the case of self-focusing material,which exhibits the same features for the case of ordinary material.In any way the self-steepening in metamaterials always tends to suppresses appearance of STI regardless of its sign.