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Updated: Aug 7, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Measurement of group refractive index wavelength dependence using a low-coherence tandem interferometer
Akiko Hirai1, Hirokazu Matsumoto
1National Institute of Advanced Industrial Science and Technology, Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan. a-hirai@aist.go.jp
Abstract:
A technique for the measurement of the group refractive index wavelength dependence of optical materials using a low-coherence tandem interferometer and a spectrometer is proposed. Four channeled spectra resulting from interferences of light beams from different pairs of optical paths are used for the calculation of optical path differences. The group refractive index wavelength dependence is calculated from these optical path differences generated from the sample under measurement. No a priori information of the geometric thickness of a sample is required. The wavelength dependence of the group refractive index of the samples BK7 parallel plate of 5.200 and 10.025 mm from 675 to 850 nm is experimentally measured with an accuracy of the order of 10(-5) and a repeatability of the order of 10(-9).
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