Reflectance method for determination of optical properties of absorbing materials

Detailed analysis of a new spectrophotometric method for determining the optical constants of absorbing materials is presented. This involves measurement of reflectances from specimens coated with transparent films delineating the bare-specimen reflectance. It is seen that this can allow preparation of specimens free from surface layers such as oxide layers and that optical constants of materials can be determined unambiguously. The refractive and absorption indices are found to be accurate up to 0.05 and 0.15 respectively, which is better than the accuracy obtained using other methods.