Depolarization and cross polarization in ellipsometry of rough surfaces

In ellipsometry of rough surfaces, the commonly used parameters, psi and delta, are insufficient to characterize completely the changes in polarization state which occur when light is reflected from a rough surface. When an experimentally determined Mueller matrix is available, parameters indicative of depolarization, cross polarization, and change in ellipticity can be found. When the Mueller matrix is regarded as an operator mapping input polarization states depicted on a Poincaré sphere to output states in a similar coordinate system, these new parameters can be illustrated in terms of their effects on the Poincaré sphere. The depolarization and cross polarization parameters correlate with specimen roughness and reflectance.