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Optical Engineering

Real-time measurement of one-dimensional step profile with a sinusoidal wavelength-scanning interferometer using double feedback control
Author(s): Osami Sasaki; Kunihiro Honma; Takamasa Suzuki
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Paper Abstract

A linear CCD image sensor is used to electrically scan a measuring point and measure 1-D step-profiles in real time with a sinusoidal wavelength-scanning (SWS) interferometer using double feedback control. In this interferometer, the optical path difference (OPD) and the amplitude of the SWS are controlled so that a ruler marking every wavelength and a ruler with scales smaller than a wavelength are generated. These two rulers enable us to measure an OPD longer than a wavelength in real time. Two different step profiles with step heights of 1 and 20 μm, respectively, are measured with a measurement error of less than 8 nm. Measuring time for one measuring point is 0.04 s.

Paper Details

Date Published: 1 June 2004
PDF: 5 pages
Opt. Eng. 43(6) doi: 10.1117/1.1737375
Published in: Optical Engineering Volume 43, Issue 6
Show Author Affiliations
Osami Sasaki, Niigata Univ. (Japan)
Kunihiro Honma, Niigata Univ. (Japan)
Takamasa Suzuki, Niigata Univ. (Japan)


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