title: Surface profiling of a transparent object by use of phase-shifting Talbot interferometry.
abstract: Talbot interferometry is used to study the surface profile of a transparent object. Periodic patterns are produced by illuminating a grating with a collimated laser beam. The object is placed on the self-image plane of the grating. The deformed grating image, which interferes with another grating, results in the Talbot interferometric fringes. The fringe pattern is recorded on a CCD camera for subsequent analysis, and the phase variation is achieved by a linear translation stage. In this application two specimens are tested to demonstrate the validity of the method; one is a transparent object with a spherical shape with a height of less than 350 microm, and the other is a transparent object with an uneven surface of 50-microm average height. The experimental results are compared with the test results obtained with the mechanical stylus method.
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. thakur_madhuri@yahoo.com
authors.forename: Madhuri
authors.initials: M
authors.lastname: Thakur
authors.forename: Cho Jui
authors.initials: CJ
authors.lastname: Tay
authors.forename: Chenggen
authors.initials: C
authors.lastname: Quan