二元台阶型光栅的校正傅里叶展开耦合波分析

Analysis for Binary Staircase Grating by Coupled-Wave Method with Corrrect Fourier Expansion

介绍了经过改进的耦合波方法。该方法通过分析介质以及电磁波在光栅矢量方向上的连续性问题 ,在计算时采用校正傅里叶展开规则 ,使计算结果取得很好的收敛。在求解透射率与反射率时 ,通过引入广义反射系数阵和透射系数阵 ,避免了病态矩阵的产生 ,使得数值计算是稳定的 ,因此可以处理大槽深、多台阶的光栅问题。同其它方法相比 ,该方法计算速度大大加快。

An improved coupled-wave method is presented in the paper.A good convergence of the calculating results has been achieved by this method through analyzing the continuity of medium and electromagnetic wave in vector direction of grating and adopting the rule of correct Fourier expansion in calculation.When solving transmittance and reflectivity,the generating of the abnormal state matrix has been avoided through introduction of generalized reflectivity matrix and transmittance matrix.In this way the numerical calculation is stable and the grating with large slot depth and multi-step can be processed.Compared with the other methods,the calculation speed of this method is largely sped up.