【作者】 钟先琼； 向安平； 程科； 蔡青；

【Author】 Zhong Xianqiong Xiang Anping Cheng Ke Cai Qing(College of Optoelectronic Technology,Chengdu University of Information Technology,Chengdu Sichuan 610225)

【机构】 成都信息工程学院光电技术学院；

【摘要】 直接从负折射介质中包含高阶色散以及饱和非线性效应的扩展非线性传输方程而不是归一化的传输方程出发,采用线性稳定性分析法和德鲁德电磁模式,解析导出了调制不稳定性的色散关系和增益谱公式。同时,考虑到今后的实验验证,本文以实际单位的形式计算了传输方程的系数随归一化角频率的变化规律。在此基础上也以实际单位的形式计算并讨论了调制不稳定增益谱随归一化角频率和归一化入射光强的变化关系。结果表明:当归一化角频率固定时,随着归一化入射光强的增加,调制不稳定性的截止频率及峰值增益都是先增加后减少的,归一化角频率不同,截止频率及峰值增益也不同,在靠近禁带处,增益谱变得远离零点。当归一化入射光强固定时,调制不稳定性的截止频率及峰值增益随着归一化角频率的增加而增加,当归一化角频率增大到靠近禁带时,增益谱由紧挨零点变成远离零点。更多还原

【Abstract】 The dispersion relation and gain spectra of modulation instability(MI) are analytically deduced in negative-index materials by directly starting from the extended nonlinear propagation equation instead of normalized one including saturable nonlinearity and high-order dispersion and by adopting the linear stability analysis and Drode electromagnetic model.And the variations of the equation coefficients with the normalized angular frequencies are calculated in real units for future experimental demonstrations.Then the variations of the gain spectra with the normalized angular frequencies and normalized optical intensities are also calculated and discussed in real units.The results show that,when the normalized angular frequencies are fixed,the cut-off frequencies and peak gains of MI increase before decrease with increase of the normalized optical intensities.And the cut-off frequencies and peak gains are different for different normalized angular frequencies.Moreover,the gain spectra will depart far away from the zero point when the normalized angular frequencies are close to the forbidden band region.When the normalized optical intensities are fixed,the cut-off frequencies and peak gains increase with the normalized angular frequencies.And when the normalized angular frequency increases to be close to the forbidden band region,the gain spectrum will shift far away from the zero point.更多还原