Abstract
The sensitivity of the reflectance vs angle of incidence method for measuring the optical constants n and k has been investigated using computer methods. Reflectance values for the perpendicular and parallel components Rs and Rp, and their average Ra, corresponding to unpolarized radiation, were computed. With these values, isoreflectance curves were plotted in the n–k plane using a computer–plotter combination. The angles of intersection of these isoreflectance curves provide a measure of the sensitivity of the method and are a function of n and k. For a given n and k, the sensitivity of the method is greatest using Rp and least using Rs Error studies showing the effects of nonparallelism and polarization of the incident radiation and error in reflectance measurement were made for Rp and Ra, but not for Rs because the lack of sensitivity of the method for this component renders it practically useless. The effect of errors was simulated by altering the computed reflectance values by a given amount and plotting the corresponding isoreflectance curves. It was found that the method is least sensitive to errors when using Rp. A scheme for plotting isoreflectance curves using a computer–plotter combination is given as well as an alternative scheme for digital computation of n and k without recourse to isoreflectance curves.
© 1965 Optical Society of America
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