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Proceedings Paper

Real-time dispersion curve measurement from spectrally resolved white-light interferometry
Author(s): Jose E. Calatroni; Carmen Sainz; Antonio L. Guerrero
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Paper Abstract

Spectrally-resolved white-light interferometry (SRWLI) is used for real-time measurement of dispersion functions. SRWLI consists in the spectroscopic analysis of the interferograms which are produced when a wide, continuous- spectrum light-source is used to illuminate a 2-wave interferometric device. This produces incoherent superposition of many monochromatic interferograms, one for each resolved wavelength in the source spectrum. Each monochromatic interferogram at wavelength (lambda) stores the optical delay in the interferometer at that particular wavelength. When a transparent, dispersive specimen is introduced in the interferometer, the optical delay becomes a function of (lambda) , and this function is stored in the incoherent superposition of the whole set of monochromatic interferograms. We propose in this paper the use of a prismatic specimen with a linear variable thickness. In this way the interferometry gives rise, for each wavelength, to a classical Young fringe pattern whose spatial frequency stores the dispersion function. The spectroscope, in series with the interferometer, splits the incoherent superposition of the different monochromatic patterns. The recorded image is processed by measuring the frequency of the fringes at each resolved wavelength. Precision in refraction index is about 10-6. The method is well adapted for measuring dispersion curves of evolving specimens because only one image is sufficient to determine the dispersion curve in the useful spectral range. Experimental results are presented for an optical glass in the visible spectrum.

Paper Details

Date Published: 17 September 1997
PDF: 8 pages
Proc. SPIE 3098, Optical Inspection and Micromeasurements II, (17 September 1997); doi: 10.1117/12.281174
Show Author Affiliations
Jose E. Calatroni, Univ. Simon Bolivar (Venezuela)
Carmen Sainz, Univ. Metropolitana (Venezuela)
Antonio L. Guerrero, Univ. Simon Bolivar (Venezuela)


Published in SPIE Proceedings Vol. 3098:
Optical Inspection and Micromeasurements II
Christophe Gorecki, Editor(s)

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