Interferometric measurement of large sphere radii using holograms

Published

July 8, 2015

Author(s)

Ulf Griesmann, Quandou (. Wang, Johannes A. Soons, Kate Medicus

Abstract

We describe a new interferometric method for the measurement of large sphere radii in which the converging test beam is replaced by a pair of test beams with different focal lengths. The test beams are created by a pair of holograms that are fabricated on a common substrate. One of the test beams is used to create a focus on the test part surface ("cats-eye"), the second test beam has its focus at the test part center of curvature ("confocal"). The distance between the two test positions can now be chosen freely during the design of the holograms. This makes it possible to measure radii of spherical surfaces that are much larger than the length of a typical radius bench with relatively small displacements and short test cavities. Uncertainties due to parasitic diffraction orders of the holograms can be reduced or eliminated when one or more of the holograms are implemented as photon sieves.

Proceedings Title

Proceeding of the ASPE Summer Topical Meeting on Precision Interferometric Metrology 2015

Conference Dates

July 8-10, 2015

Conference Location

Golden, CO

Conference Title

ASPE Summer Topical Meeting on Precision Interferometric Metrology

Pub Type

Conferences

Keywords

Interferometry, radius measurement, diffractive optics

Citation

Griesmann, U. , Wang, Q. , Soons, J. and Medicus, K. (2015), Interferometric measurement of large sphere radii using holograms, Proceeding of the ASPE Summer Topical Meeting on Precision Interferometric Metrology 2015, Golden, CO (Accessed October 20, 2025)