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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 17 — Aug. 17, 2009
  • pp: 15104–15117

White-light scanning interferometer for absolute nano-scale gap thickness measurement

Zhiguang Xu, Vijay Shilpiekandula, Kamal Youcef-toumi, and Soon Fatt Yoon  »View Author Affiliations

Optics Express, Vol. 17, Issue 17, pp. 15104-15117 (2009)

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A special configuration of white-light scanning interferometer is described for measuring the absolute air gap thickness between two planar plates brought into close proximity. The measured gap is not located in any interference arm of the interferometer, but acts as an amplitude-and-phase modulator of the light source. Compared with the common white-light interferometer our approach avoids the influence of the chromatic dispersion of the planar plates on the gap thickness quantification. It covers a large measurement range of from approximate contact to tens of microns with a high resolution of 0.1 nm. Detailed analytical models are presented and signal-processing algorithms based on convolution and correlation techniques are developed. Practical measurements are carried out and the experimental results match well with the analysis and simulation. Short-time and long-time repeatabilities are both tested to prove the high performance of our method.

© 2009 Optical Society of America

OCIS Codes
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.3940) Instrumentation, measurement, and metrology : Metrology
(120.4640) Instrumentation, measurement, and metrology : Optical instruments

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: May 28, 2009
Revised Manuscript: June 29, 2009
Manuscript Accepted: July 9, 2009
Published: August 11, 2009

Zhiguang Xu, Vijay Shilpiekandula, Kamal Youcef-toumi, and Soon Fatt Yoon, "White-light scanning interferometer for absolute nano-scale gap thickness measurement," Opt. Express 17, 15104-15117 (2009)

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