Distortion compensation in interferometric testing of mirrors.
Brian M Robinson1, Patrick J Reardon
1University of Alabama in Huntsville, Center for Applied Optics, 301 Sparkman Drive, Optics Building Room 400, Huntsville, Alabama 35899, USA. Brian.Robinson@uah.edu
Applied Optics
|January 20, 2009
Summary
We developed a new method to correct imaging distortion in mirror interferometry without surface fiducials. This technique accurately maps grid coordinates to the mirror
Area of Science:
- Optical engineering
- Metrology
- Surface testing
Background:
- Interferometric testing of mirrors is crucial for precision optics.
- Imaging distortions arise from interferometer optics and geometric projection.
- Existing methods may require surface modifications (fiducials).
Purpose of the Study:
- To present a novel method for compensating imaging distortion in interferometric mirror testing.
- To enable distortion correction without applying fiducials to finished mirror surfaces.
Main Methods:
- A mask with a regular square grid is placed over the mirror.
- A transformation is calculated relating grid coordinates to the parent surface's base plane coordinates.
- Grid coordinates are projected onto the mirror base plane before regression analysis.
Main Results:
- The method successfully compensates for imaging distortion.
- The technique was validated on an F/2 off-axis paraboloid using a center-of-curvature null test.
Conclusions:
- The presented method offers a non-invasive approach to correct interferometric imaging distortion.
- This technique enhances the accuracy of mirror surface testing, particularly for complex optical components.
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