Measuring the radius of curvature of a spherical mirror with an interferometer and a laser tracker

We present a method to accurately measure the radius of curvature of a concave spherical mirror with a phase-measuring interferometer and a laser tracker. Use of a laser tracker eases the alignment of the testing system, eliminates the need to move the test piece during the mea- surement, and improves the accuracy of the distance mea- surement. Using this method, we measured the radius of curvature of a spherical mirror 0.5 m in diameter and about 2.5 m in radius of curvature. The accuracy of the measure- ment is better than ±20 m. © 2005 Society of Photo-Optical Instru- mentation Engineers. DOI: 10.1117/1.2047594