用矢量Rayleigh-Sommerfeld(VRS)衍射理论分析计算了高数值孔径多台阶相幅型菲涅耳波带片(M-SHFZP)的聚焦场分布。当线性偏振光垂直入射到M-SHFZP，结果显示: 1) 由于薄膜透射率随着刻蚀台阶深度发生变化，致使实际的M-SHFZP 的聚焦强度小于多台阶纯相位型菲涅耳波带片(M-SPFZP)的聚焦强度，但是M-SHFZP 的聚焦光斑大小基本上与M-SPFZP 的相同；2) 聚焦光的强度随着台阶数的增加而增加，但聚焦光斑的大小不随台阶数变化；3) 对于低数值孔径的M-SHFZP，光轴上的强度呈现一个多焦点分布，但是对于高数值孔径的M-SHFZP，高级焦点的强度被大大抑制。台阶数愈多，数值孔径愈大，抑制高级次焦点的能力愈强。VRS 矢量衍射理论的计算结果与时域有限差分法(FDTD)模拟结果基本一致。

The vertical Rayleigh-Sommerfeld (VRS) diffraction theory is used for analyzing and calculating the focused field distributions of high-numerical-aperture (NA) multi-step hybrid Fresnel zone plates (M-SHFZP). Under the illumination of linearly-polarized light, results are shown as follows: 1) Due to the transmission coefficient of the film changing with the depth of steps, the focused intensity of M-SHFZP is smaller than that of multi-step pure-phase Fresnel zone plates (M-SPFZP). However, the focal spot size of M-SHFZP is almost the same as that of M-SPFZP; 2) As the step number increases, the focused intensity increases, but the spot size is invariant; 3) The diffraction field presents a multispot distribution for low-NA M-SHFZP, but the intensity of high-order foci is effectively suppressed for high-NA M-SHFZP. The more the step number and the higher the NA, the stronger the ability of M-SPFZP to suppress higher-order foci. The results obtained by the VRS agree with the results obtained from the finite-different time-domain (FDTD) simulation basically.