Photometric methods for determining the optical constants and the thicknesses of thin absorbing films: criteria for precise and unambiguous determination of n, k, and d in a wide spectral range.

The application of error analysis within a certain algorithm for the most accurate and unambiguous determination of refractive index n, absorption coefficient k, and thickness d of thin absorbing films in a wide spectral range is illustrated with three examples. Thin films of a dye, Ag, and Au are selected because their optical constants (small n for Ag and Au and considerable variations of n and k for the dye films) along with their thinness make investigating these thin films difficult. The important steps of the algorithm that ensure reliable isolation of the physically correct solutions and maximum accuracy of n and k in the spectral range investigated are also demonstrated.