Research on wavefront and focal position alignment technology for off-axis three-mirror optical systems

Abstract

The off-axis three-mirror optical system is extensively utilized in space and terrestrial observation. Such system encounters significant challenges in alignment due to multiple degrees of freedom (DOF). This study proposes a computer-aided alignment (CAA) framework to address multi-objective optimization problems including wavefront and focus position. Firstly, the sensitivity matrix is established using Python+Zemax simulation to quantify the relationship between misalignment and aberrations. Singular Value Decomposition is applied to identify critical DOF for correction. Innovatively, adaptive damping least squares concerning position deviation (ADLS-P) algorithm is developed to simultaneously correct wavefront and focus position deviation, overcoming the conventional limitation of neglecting focus shifts. Simulation and experimental validations are successfully conducted, achieving full-field wavefront aberration better than 0.06λ@632.8 nm and focus deviation under 0.1 mm for a typical off-axis three-mirror system. This work bridges the gap in multi-target correction and establishes a new paradigm for active alignment through synergistic wavefront-focus optimization.