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Proceedings Paper

A simple ball averager for reference sphere calibrations
Author(s): Ulf Griesmann; Quandou Wang; Johannes Soons; Remi Carakos
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Paper Abstract

When measuring the form errors of precision optics with an interferometer, calibration of the reference wavefront is of central importance. In recent years, ball averaging, or random ball testing, has emerged as a robust method for calibrating spherical reference wavefronts in converging beams. We describe a simple instrument, consisting of an air bearing and two electric motors, that can rotate the test ball around three axes as required for a ball averaging test. The performance of the instrument is demonstrated by using it to calibrate a concave transmission sphere. Further we discuss the effects of image sampling at random locations or on uniform grids, and the effect of correlated measurements. Finally, we describe a method to determine the number of measurements which are sufficient for a ball averaging calibration.

Paper Details

Date Published: 20 August 2005
PDF: 8 pages
Proc. SPIE 5869, Optical Manufacturing and Testing VI, 58690S (20 August 2005); doi: 10.1117/12.614992
Show Author Affiliations
Ulf Griesmann, National Institute of Standards and Technology (United States)
Quandou Wang, National Institute of Standards and Technology (United States)
Johannes Soons, National Institute of Standards and Technology (United States)
Remi Carakos, National Institute of Standards and Technology (United States)


Published in SPIE Proceedings Vol. 5869:
Optical Manufacturing and Testing VI
H. Philip Stahl, Editor(s)

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