title: Noncollimated bidirectional shearing interferometer for measuring a long radius of curvature.
abstract: A method for measuring a long radius of curvature with a modified half-aperture bidirectional shearing interferometer is described. A plane mirror of the interferometer is replaced with a test mirror, and the incident beam is decollimated by shifting of the source to equalize the widths of the bidirectional shearing fringes reflected from the plane and test mirrors. This method can be applied to concave and convex surfaces.
authors.affiliation: Quantum Metrology Division, Korea Research Institute of Standards and Science, P. O. Box 102, Yusong, Taejon, 305-600, South Korea.
authors.forename: Y W
authors.initials: YW
authors.lastname: Lee
authors.forename: H M
authors.initials: HM
authors.lastname: Cho
authors.forename: D J
authors.initials: DJ
authors.lastname: Shin
authors.forename: I W
authors.initials: IW
authors.lastname: Lee