光盘光学系统的矢量衍射理论分析

本文以完整的矢量衍射理论分析了光盘光学系统。首先将入射的聚焦光束分解为平面波谱 ,得到每个平面波的振幅矢量 ;然后计算光盘对每个平面波的衍射 ,得到衍射波的振幅矢量 ,从而得到了整个衍射波场的空间频谱 ;最后计算物镜光瞳上的能通量 ,得到光盘系统的读出信号。在衍射计算中 ,光盘被定义为二维金属光栅 ,根据信息符的不同模型 ,选用坐标变换方法、耦合波方法或模态方法。对于典型的 DVD光学系统来说 ,矢量理论的结论与标量理论相差甚远 ,要得到正确的结果就必须采用矢量衍射理论

Vector diffraction theory for optical disk system

A full vector diffraction theory for optical disk system is described. Firstly the focused incident beam is decomposed into a spectrum of plane waves, and the amplitude vector of each plane wave is acquired. Then the amplitude vectors of diffracted plane waves from the disk are calculated rigorously for each incident plane wave, and the spatial frequency spectrum of the total diffracted field is obtained. Finally the energy flux over the objective pupil is calculated and the read out signal of the optical disk system is obtained. In the diffraction calculation, the optical disk is modeled as a crossed metal grating, coordinate transformation method, coupled wave theory and modal method can be adopted according to the different modals of the information marker. The result of vector theory is far from that of the traditional scalar diffraction theory for a typical DVD system, so vector diffraction theory must be adopted.