为了实现高精度大口径平行光管波前检测, 评价平行光管出射波前质量, 提出了采用差分五棱镜扫描波前检测方法检测平行光管。该方法为五棱镜扫描法的优化方法, 通过测量波前斜率的改变得到波前曲率的信息来重构波前, 从而消除由于五棱镜扫描法波前检测中质心标定不准确而引入的倾斜和离焦的误差量。通过搭建差分五棱镜扫描法波前检测系统验证了此方法的可行性, 并给出差分五棱镜扫描法误差分析说明此方法可靠性。误差分析表明, 该方法检测精度可以达到10.54 nm; 实验结果表明, 该方法相比于五棱镜扫描法分别在波面峰谷值（PV）和均方根值（RMS）的重复性精度上提高了74.41%和125.81%。该方法基本满足平行光管波前检测精度高、稳定性好的要求, 可以客观准确地评价平行光管出射波前质量。

In order to realize the high precise wavefront test of large-aperture collimator and evaluate its wavefront quality, the method of differential pentaprism scanning wavefront detection is proposed in this paper. This method is the optimization of pentaprism scanning detection. Firstly, the information of wavefront curvature is obtained by measuring wavefront slope change to reconstruct the wavefront. The title and defocus error instructed by inaccurate calibration of center of mass are eliminated. Secondly, the differential pentaprism scanning wavefront detection system is established to verify the feasibility of this method. Lastly, the error analysis is given. The error analysis shows that the testing precise of this method is 10.54 nm. The experimental results show that the repeatability precisions of wave peak and valley value(PV) and root mean square(RMS) are increased by 74.41% and 125.81% compared with pentaprism scanning method. This method basically meets the requirements of high accuracy and good stability for collimator wavefront detection, which can be used to evaluate the quality of collimator wavefront.