Calculation of the optical constants of a thin layer upon a transparent substrate from the reflection spectrum

A method has been proposed for calculation of the optical constants of a thin layer upon a transparent substrate only from the reflection spectrum into the region of transmission of the layer. The envelopes of the maxima of the spectrum R_M and of the minima R_m are used, taking into account the finite dimensions of the substrate. The algorithm of the calculations is similar to the one proposed by Swanepoel (1983) using the transmission spectrum. The method makes it possible to calculate the thickness of the layer and the refractive index n with an error of 0.2%. The correct description of the dispersive relationship of n is obtained for an amorphous layer Ge₁₉As₂₁S₆₀.