使用衍射光学元件（DOE）作为投影光刻照明系统实现离轴照明（OAI）的光束整形匀光器件，能够在保持较高照明效率的基础上精确控制OAI光束的形状及光强分布。在矢量角谱传输方法的基础上，建立了投影光刻用DOE的矢量分析模型，并对标量方法设计的DOE在偏振照明情况下的匀光与整形性能进行了分析。分析结果表明DOE在大角度衍射、单元尺寸与工作波长相近条件下，一般标量近似条件已不满足，仍采用标量迭代方法进行DOE设计，则计算结果存在较大误差。

The description of a plane wave diffracted by a circular aperture is directly started from the Maxwell's equations. Based on the vector angular spectrum representation of Maxwell's equations, the diffracted plane wave is decomposed into the TE and TM terms. The analytical TE and TM terms in the far field are presented by stationary phase. As the TE and TM terms are orthogonal to each other in the far field, their sum constitutes the so-called Airy disc pattern. Therefore, this research reveals the composition of Airy disc, which is beneficial to deepen and enhance the recognition of the classical diffraction problem.