A novel compensation method for the measurement of radius of curvature

A test method for spherical mirrors with super-long radius of curvature that only one compensator is employed to measure the radii of curvature of both concave and convex mirrors is presented. With this testing system, the surface figure and radius of curvature of spherical mirrors can be measured simultaneously. Using the ABCD matrix method, a precise formula for radius of curvature calculation is deduced. Experimental results show that the relative measurement error of this method is less than 4.2×10 −4.