Traditional interferometric profilemeter suffers from phase ambiguity problem and sensitivity to environmental disturbance, thus preventing their applications for on-line surface inspections. We propose a new method to obtain the object surface's two-dimensional profile in a single shot using a dispersive interferometer. An air-spaced Fabry-Perot etalon was applied in order to decompose the light from the broadband source into discrete monochromatic constituents with equal wavelength interval. A blazed grating is implemented to effectively separate the interferograms of difference wavelength. As a result, the interference patterns of different wavelengths distributed separately on the CCD camera. By analyzing these patterns one can get the configuration of the original surface. A one-dimensional profiling experiment is carried out to test a surface with steps and the mean error of the result is below 0.2μm.

Date Published: 9 November 2010
PDF: 7 pages
Proc. SPIE 7849, Optical Design and Testing IV, 78491A (9 November 2010); doi: 10.1117/12.869987

Published in SPIE Proceedings Vol. 7849:
Optical Design and Testing IV
Yongtian Wang; Julie Bentley; Chunlei Du; Kimio Tatsuno; Hendrik P. Urbach, Editor(s)