Optical Nanostructures Laboratory, Columbia University, New York, New York 10027, USA.
Opt Lett. 2011 Jun 15;36(12):2239-41. doi: 10.1364/OL.36.002239.
We examine the effects of multiphoton absorption, free carriers, and disorder-induced linear scattering in slow-light photonic crystal waveguides. We derive an analytic formulation for self-phase modulation including the group velocity scaling of the nonlinear phase shift in materials limited by three-photon absorption as a representative nonlinear process. We investigate the role of free carriers and derive an approximate critical intensity at which these effects begin to strongly modify the optical field. This critical intensity is employed to determine an optimal group index for the self-phase modulation in the slow-light devices. These observations are confirmed with numerical modeling.
我们研究了多光子吸收、自由载流子和无序诱导的线性散射对慢光光子晶体波导的影响。我们推导出了自相位调制的解析公式，包括由三光子吸收限制的材料中非线性相移的群速度缩放。我们研究了自由载流子的作用，并推导出了一个近似的临界强度，在这个强度下，这些效应开始强烈地改变光场。这个临界强度被用来确定慢光器件中自相位调制的最佳群折射率。这些观察结果得到了数值模拟的证实。
