Abstract

A numerical method is developed for eliminating the interference fringes from infrared absorption spectra of film measured with a spectrophotometer. The method uses the data of two spectra of a film sample, each obtained by the spectrophotometer at a different incident angle. The result is an optical-constant spectrum without a contribution of interference fringes. The absolute thickness of the film is also found. The simplex method is used for minimizing the squared error between two estimated absorbances per the unit length calculated from the two spectra. Experimental results are shown to demonstrate the effectiveness of the method.

© 1991 Optical Society of America

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