Determining the refractive index dispersion and thickness of hot-pressed chalcogenide thin films from an improved Swanepoel method

Fang, Y. and Jayasuriya, D. and Furniss, D. and Tang, Z.Q. and Sojka, Ł. and Markos, C. and Sujecki, S. and Seddon, A.B. and Benson, T.M. (2017) Determining the refractive index dispersion and thickness of hot-pressed chalcogenide thin films from an improved Swanepoel method. Optical and Quantum Electronics . ISSN 1572-817X (In Press)

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Abstract

The well-known method presented by Swanepoel can be used to determine the refractive index dispersion of thin films in the near-infrared region from wavelength values at maxima and minima, only, of the transmission interference fringes. In order to extend this method into the mid-infrared (MIR) spectral region (our measurements are over the wavelength range from 2 to 25 μm), the method is improved by using a two-term Sellmeier model instead of the Cauchy model as the dispersive equation. Chalcogenide thin films of nominal batch composition As40Se60 (atomic %) and Ge16As24Se15.5Te44.5 (atomic %) are prepared by a hot-pressing technique. The refractive index dispersion of the chalcogenide thin films is determined by the improved method with a standard deviation of less than 0.0027. The accuracy of the method is shown to be better than 0.4% at a wavelength of 3.1 μm by comparison with a benchmark refractive index value obtained from prism measurements on Ge16As24Se15.5Te44.5 material taken from the same batch.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Engineering
Depositing User: Eprints, Support
Date Deposited: 01 Jun 2017 13:12
Last Modified: 02 Jun 2017 16:21
URI: http://eprints.nottingham.ac.uk/id/eprint/43329

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