Error-separation model for interferometric testing aspheric surfaces based on wavefront aberrations

During interferometric testing, an objective, accurate evaluation of the surface information is one of the key factors needed to realize fast, deterministic manufacturing of large off-axis aspheric mirrors. An error-separation matrix for analysis of the error information in the testing results was developed by modeling the aspheric surface as a rigid body with five degrees of freedom. Wavefront aberration theory was used to find expressions for the adjustment errors and parameters for computerized testing of large aperture off-axis aspheric mirrors. Simulations correctly predicted interferometric patterns corresponding to different adjustment errors so the simulations can be used to quickly adjust the test system.