为了验证多层衍射光学元件的衍射效率随入射角度的理论变化关系，设计并制作了一个含有多层衍射光学元件（MLDOEs）的光学系统。当次级衍射光通过孔径光阑由探测器接收时，为保证衍射效率的测量精度，提出了一级衍射能量的修正方法。利用搭建的双光路装置，在0°~30.6°范围内对该多层衍射光学元件进行了衍射效率的测量。针对设计波长532 nm，选取7个入射角度测量衍射效率，并对测量结果进行了模拟和分析。由于存在一定的加工误差，在不同入射角度状态下实际测量得到的衍射效率比理论分析的结果低，但是实测与理论分析结果均表明，多层衍射光学元件的衍射效率随入射角的增大而下降。

In order to verify the theoretical relationship of the diffraction efficiency of multi-layer diffractive optical elements varying with the angle of incidence, an optical system with multi-layer diffractive optical elements is designed and manufactured. To ensure the measurement accuracy of diffraction efficiency when light of secondary order diffraction is received by the detector after passing through the pinhole aperture, a correction method of first-order diffraction energy is proposed. The diffraction efficiency of the multi-layer diffractive optical elements with the incident angles ranging from 0° to 30.6° is measured by the established double light-path measurement device. Diffraction efficiency is measured at seven different incident angles with the designed wavelength of 532 nm, and the measurement results are simulated and analyzed. Due to some manufacturing errors, the diffraction efficiency obtained by the actual measurement is lower than the theoretical analysis results. However, both measured and theoretical results show that the diffraction efficiency of multi-layer diffractive optical elements declines with the increase of incident angle.