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Optical Engineering

Three-dimensional step–height measurement using sinusoidal wavelength scanning interferometer with four-step phase-shift method
Author(s): Samuel Choi; Shouhei Takahashi; Osami Sasaki; Takamasa Suzuki
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Paper Abstract

A sinusoidal wavelength scanning interferometer with the four-step phase-shift method is demonstrated for a three-dimensional profile measurement. The interference phase-shift signal generated by the sinusoidal wavelength scanning contains information about optical path difference covering a nm-μm scale structure. The interference phase-shift signal was obtained by the four-step phase-shifting method. The sinusoidal wavelength shifting with a frequency of approximately 180 Hz and tunable range of 5.7 nm was performed by the Littman–Metcalf external resonator-type tunable laser with a center of 772.1 nm. The full-field surface profile measurement was conducted by a charge coupled device image sensor with an accuracy on a nm scale. The surface profiles of gauge blocks with a step height up to about 10  μm were successfully measured with a surface profile irregularity of 3.8×10−2  μm. The deviations of two measured surfaces of upper and lower steps were estimated to be 1.6×10−2  μm and 3.1×10−2  μm, respectively.

Paper Details

Date Published: 21 August 2014
PDF: 6 pages
Opt. Eng. 53(8) 084110 doi: 10.1117/1.OE.53.8.084110
Published in: Optical Engineering Volume 53, Issue 8
Show Author Affiliations
Samuel Choi, Niigata Univ. (Japan)
Shouhei Takahashi, Niigata Univ. (Japan)
Osami Sasaki, Niigata Univ. (Japan)
Takamasa Suzuki, Niigata Univ. (Japan)

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