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Applied Optics

Applied Optics


  • Vol. 42, Iss. 19 — Jul. 1, 2003
  • pp: 3882–3887

Method for measuring the refractive index and the thickness of transparent plates with a lateral-shear, wavelength-scanning interferometer

Giuseppe Coppola, Pietro Ferraro, Mario Iodice, and Sergio De Nicola  »View Author Affiliations

Applied Optics, Vol. 42, Issue 19, pp. 3882-3887 (2003)

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A new method for measuring simultaneously the thickness and the refractive index of a transparent plate is proposed. The method is based on a simple, variable lateral-shear, wavelength-scanning interferometer. To achieve highly accurate measurements of both refractive index n and thickness d we use several means to determine these two quantities. We finely tune a distributed-feedback diode laser light source to introduce a phase shift into the detected signal, whereas we make the sample rotate to produce variable lateral shearing. Phase shifting permits precise determination of the optical thickness, nd, whereas refractive index n is obtained from the retrieved phase of the overall interference signal for all incidence angles.

© 2003 Optical Society of America

OCIS Codes
(120.2650) Instrumentation, measurement, and metrology : Fringe analysis
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
(220.4840) Optical design and fabrication : Testing

Original Manuscript: October 17, 2002
Revised Manuscript: February 25, 2003
Published: July 1, 2003

Giuseppe Coppola, Pietro Ferraro, Mario Iodice, and Sergio De Nicola, "Method for measuring the refractive index and the thickness of transparent plates with a lateral-shear, wavelength-scanning interferometer," Appl. Opt. 42, 3882-3887 (2003)

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