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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 15, Iss. 15 — Jul. 23, 2007
  • pp: 9470–9475

Liquid refractometer based on immersion diffractometry

Sheng-Hua Lu, Shan-Peng Pan, Tzong-Shi Liu, and Ching-Fen Kao  »View Author Affiliations

Optics Express, Vol. 15, Issue 15, pp. 9470-9475 (2007)

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This study presents a laser diffractometric refractometer for measuring the refractive index of liquids. The refractive index is determined by rotating a reflection grating that is immersed in the fluid under test, and measuring the first-order Littrow diffraction angle. The Littrow angle is easily detected form the interferogram formed by the diffracted beam from the grating and the reflected beam from the liquid surface. No special cell for liquids is required. The alignment and measuring processes are simpler than those of other refractometers. The results of a feasibility experiment reveal that the accuracy of the proposed approach is about 0.003 for a refractive index of around 1.3.

© 2007 Optical Society of America

OCIS Codes
(050.1950) Diffraction and gratings : Diffraction gratings
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(120.4640) Instrumentation, measurement, and metrology : Optical instruments

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: May 29, 2007
Revised Manuscript: July 12, 2007
Manuscript Accepted: July 14, 2007
Published: July 17, 2007

Sheng-Hua Lu, Shang-Peng Pan, Tzong-Shi Liu, and Ching-Fen Kao, "Liquid refractometer based on immersion diffractometry," Opt. Express 15, 9470-9475 (2007)

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