Analytical method of determining optical constants of a weakly absorbing thin film

We propose an analytical method for determining the refractive index and the extinction coefficient of a weakly absorbing thin film. This method is based on measurements of the reflectance extreme and corresponding transmittance of the film at normal incidence. Simulations of the theoretical accuracy of the method are given. The effect of the errors of reflectance and transmittance measurements on determination of the optical constants is also analyzed. The method is successfully applied to calculate the optical constants of indium tin oxide films.