title: Measurement of profiles along a circle on two flat surfaces by use of a Fizeau interferometer with no standard.
abstract: A method for measuring profiles along a circle on a flat surface with no standard is described. For the measurement, two unknown surfaces are placed almost parallel, and the distance between them is measured many times along a circle by rotation of one of the surfaces. Profiles of the two surfaces can be determined from the distance data. In this study the measuring method is explained: The space between two surfaces measured with a Fizeau interferometer. Four measuring experiments are carried out for determining the profile of a precision-grade half-mirror; in each experiment a different ordinary mirror with unknown profile is used as the second mirror. Profiles of the precise mirrors obtained by these experiments agree closely, with deviations of approximately 2 nm. A similar experiment with many concentric circles was carried out with a precise half-mirror and another precise mirror. Although the profiles of many concentric circles were independent of one another, the result shows that the high-frequency component of a whole plane can be estimated.
authors.affiliation: Takamatsu National College of Technology, 355 Chokushi, Takamatsu, Kagawa, 761-8058 Japan. sonozaki@takamatsu-nct.ac.jp
authors.forename: Shohachi
authors.initials: S
authors.lastname: Sonozaki
authors.forename: Koichi
authors.initials: K
authors.lastname: Iwata
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Iwahashi