利用离轴三反镜光学系统确定各镜的装调公差

Study on decision of alignment priority using mirror tolerance in a three mirror off-axis optical system

利用条纹泽尼克系数与赛德尔像差的关系,在三反镜光学系统的出瞳面上,用条纹泽尼克系数来表示系统的波像差。通过光学设计软件Zemax计算得到三反镜光学系统各镜的装调公差,以公差要求高的镜面作为装调基面,从而减少要调整的自由度。通过分析泽尼克(Zernike)系数在公差范围内的变化幅度来确定光学系统在出瞳面上各个像差的变化幅度,用该幅度的变化量来决定主次三镜各自由度在各个方向上的敏感度,最终确定各个自由度的优化调整级别。对一大口径无遮拦离轴三反镜光学系统进行了装调,在波长λ=632.8nm的条件下进行了检测。结果表明:整个光学系统全视场波前误差的均方根值RMS=0.108λ。

According to relation between fringe Zernike coefficients and Seidel aberration, wavefront aberration in the exit pupil of optical system is instead with fringe. Zernike coefficient. Then calculating the alignment tolerance of three mirror off-axis optical system with optical design software Zemax, the basic mirror which have a tighten tolerance is confirmed, it can reduce the adjustment freedom. Then analyzing the change of fringe Zernike coefficient in the exit pupil, the change of aberration such as astigmatism, coma and direct the priority of freedom of mirror are determined. For a large-aperture, off-axis, three mirror optical system, optical system wavefront error RMS is 0.108A at γ = 632.8 nm with this method.