We report a simple method of measuring the absolute values of the phase refractive index of an optical material of a flat plate shape over a wide spectral range at a single measurement run. A white-light interferometric technique with angle rotation of the optical plate sample located in one of the interfer ometer arms was used in this method. The validity of this method was proved by measuring the absolute phase refractive indices of flat plate samples of fused silica and BK7, and by comparing them with calculated values from their well-known Sellmeier dispersion formulas. The accuracy of this refractive index measurement method was within 0.002, which can be further improved by enhancing the angle measurement accuracy of the angle rotating stage used in this method.
© 2010 Optical Society of America
Original Manuscript: November 18, 2009
Revised Manuscript: January 11, 2010
Manuscript Accepted: January 18, 2010
Published: February 8, 2010
Seung Hwan Kim, Seoung Hun Lee, Jae In Lim, and Kyong Hon Kim, "Absolute refractive index measurement method over a broad wavelength region based on white-light interferometry," Appl. Opt. 49, 910-914 (2010)