饱和非线性效应对负折射材料中孤子自频移的影响

The Influence of Saturable Nonlinearity on Raman Soliton Self-frequency in Negative Refraction Materials

以描述负折射材料中包含拉曼效应的高阶非线性薛定谔方程为模型,采用分步傅里叶算法数值分析了高阶效应,尤其是饱和非线性效应对自聚焦负折射率材料中的孤子拉曼自频移的影响。结果表明,在自聚焦负折射率材料中饱和非线性效应使孤子拉曼自频移速度加快;饱和非线性效应与负的自陡效应共同作用进一步加快孤子自频移的速度;饱和非线性效应同正的自陡效应、三阶色散效应共同作用时孤子拉曼自频移在整体上受到抑制。

Based on the model of nonlinear Schrodinger equation with Raman effect describing propagation of ultrashort pulse in negative refraction materials, the influence of the high-order effects, especially saturable nonlinearity effect, on Raman soliton self-frequency in self-focusing negative refraction materials was studied with the split-step Fourier method. It was showed that in self-focusing negative refraction material, the soliton self-frequency shift was accelerated under the saturable nonlinearity effect,and the soliton self- frequency shift was further accelerated under the saturable nonlinearity combined with negative self-steepening effect, while the soliton self-frequency shift was effectively suppressed under the saturable nonlinearity combined with positive self-steepening and third-order dispersion effects.