Enabling precision coordinate metrology for universal optical testing and alignment applications

• Published in: Optical engineering 2021-03, Vol.60 (3), p.035106-035106
• Main Authors: Khreishi, Manal, Ohl, Raymond G, Howard, Joseph M, Papa, Jonathan C, Mcclelland, Ryan, Hovis, Clark, Hadjimichael, Theodore, Thompson, Patrick, Ranson, Kenneth, Liang, Rongguang, Gorius, Nicolas
• Format: Article
• Language: English
• ISSN: 0091-3286; 1560-2303
• DOI: 10.1117/1.OE.60.3.035106

Optical designs for the next generation space science instruments call for unconventional, aspheric, and freeform (FF), prescriptions with tight tolerances. These advanced surfaces enable superior-performance, compact, and lower cost systems but are more challenging to characterize and, hence, to fabricate and integrate. A method was developed to characterize a wide range of optical surfaces, without requiring custom-made correctors, and to align them to each other for a high-performance optical system. A precision coordinate measuring machine, equipped with a non-contact, chromatic confocal probe, was used to measure numerous optics including large convex conics, high-sloped aspherics, several FF surfaces, and grazing-incidence x-ray optics. The resulting data were successfully reduced using custom-developed, advanced surface fitting analysis tool, to determine the optic’s alignment relative to the global and local coordinate systems, surface departure from design, and the as-built optical prescription. This information guided the modeling and the alignment of the corresponding as-built optical systems, including a flight system composed of a three-mirror anastigmat.