Surface-roughness effects on the determination of optical properties of materials by the reflection method

The effects of surface roughness on the determination of the optical properties of materials by the reflection method were investigated. We showed that the refractive indices of a material with a moderately rough surface can be obtained by the reflection method, provided that the radio of the angular reflectances at both states of polarization is known. Specifically, we showed that for a nonspecular surface with specularity index as low as 0.07 the real and imaginary parts of the complex refractive index can be determined with an average deviation from its actual value of 2.9% and 5.0%, respectively.