作为零位干涉检测方法中非常有前途的一种方法,计算全息可以用于非旋转对称的非球面的检测。以三次相位板为例,阐述了利用计算全息图检测非旋转对称的非球面的基本原理。分析并推导了三次相位传播过程引入的高阶波像差的理论公式,给出了三次相位板的检测系统的设计结果。详细讨论了计算全息图衍射级次的分离以及计算全息图的二元化,给出了振幅型的计算全息图的图样。计算全息图的刻线最小间隔是40 μm,计算全息图的制作精度对检测结果的波前误差的影响仅仅为0.005λ。对检测系统作了详细的公差分析,结果表明所有调整公差对整个检测系统的影响和方根值为83.954 nm。

As one of the most promising methods in all the interferometric null tests, computer-generated holograms (CGH) can also be used in unsymmetrical aspherical surfaces testing. Taking the cubic surface as an example, the principle of testing unsymmetrical aspherical surfaces with CGH is given. The expression of the aberration for the cubic phase during propagation is deduced, and the results of the optical design for the cubic surface test system are listed. The separation of diffraction orders and the binary process of the continuous CGH phase function are discussed in detail, and the sample of the amplitude CGH is given. The minimum line spacing of the CGH is 40 μm and its effect on wavefront error is only 0.005λ. The tolerance analysis of testing system is done in detail, and the total effect from all alignment tolerances that affect testing system is 83.954 nm (root-mean-square).