Abstract: To address the challenges of processing and testing high order aspherical surface with large aperture and large relative aperture, an autocollimation correction compensation testing method similar to the Offner structure is proposed. The method involves coating a semi-transparent and semi-reflective film on the side of the compensator that is far away from the aspherical reflector to be tested. By repeatedly using the compensator, the autocollimation correction function of the light can be achieved, thus completing the full aperture testing of large relative aperture aspherical surfaces. Firstly, based on the three-level aberration theory, the formula for calculating the initial structural parameters of the optical testing system is deduced. And then, the simulation and design of the optical testing system for the high-order aspherical surface with an effective aperture of 712 mm and F/0.58 concave are carried out, and it shows that the peak to valley (PV) value of the residual wave aberration after system optimization is 0.0656 λ, and the root mean square (RMS) value is 0.0104 λ (λ=632.8 nm). Finally, an analysis of the actual testing situation is conducted, and it is found that the designed autocollimation correction compensation testing system can meet the requirements of the actual testing. This work demonstrates that the proposed autocollimation correction compensation testing method similar to the Offner structure can solve the problem of compensation testing for large relative aperture high order aspherical surfaces.

Key words: optical aspheric testing, compensator design, autocollimation correction compensation testing, large relative aperture