title: Determination of small angular displacement by moiré fringes of matched radial-parallel gratings.
abstract: We investigate the properties of the moiré fringes of matched radial-parallel (MRP) gratings that are useful for the fine visual indication of angular displacements. Moiré patterns formed by overlapping two different MRP gratings of angular pitches, P(theta) and P(theta)? (<P(theta)), can provide a simple fringe-counting method for determining both the angle and the direction of the relative angular displacement of the gratings within the accuracy of (P(theta)?/M(theta)), where M(theta) is the angular magnification for radial vernier fringes.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kim
authors.forename: J S
authors.initials: JS
authors.lastname: Song
authors.forename: J T
authors.initials: JT
authors.lastname: Kim
authors.forename: J H
authors.initials: JH
authors.lastname: Jo
authors.forename: S
authors.initials: S
authors.lastname: Chang
authors.forename: K C
authors.initials: KC
authors.lastname: Yuk