30 June 1998 Direct group-delay measurement and 3D profilometry using a white-light interferometer
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Abstract
A white light interferometer based on a single beamsplitter is described for direct group delay measurements. The arms of a Mach-Zehnder interferometer are folded in such a manner that a single beamsplitter could be used for splitting the incoming beam and combining the outgoing beams. This method offers a two-fold advantage: the measuring range of this interferometer is twice as large as that of the Michelson interferometer and the systematic error associated with the beamsplitter is minimized due to its configuration. We report the result of measurements on optical components performed in the 560nm to 630nm spectral region and propose a scheme for the processing of the experimental data. The principle of this group delay measurement procedure is then applied to construct a dispersive interferometric 3D profilometer. By adding the dispersion optics in one of the arms in the profilometer head, which consists of a Michelson interferometer, the practical dynamic range of the profilometer can be easily extended beyond one hundred micrometers.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yi Liang, Q. M. Jonathan Wu, Chander Prakash Grover, "Direct group-delay measurement and 3D profilometry using a white-light interferometer", Proc. SPIE 3478, Laser Interferometry IX: Techniques and Analysis, (30 June 1998); doi: 10.1117/12.312974; https://doi.org/10.1117/12.312974
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