Optimum angles for determining the optical constants from reflectivity measurements

Avery's and Simon's reflection methods for determining the optical constants n and k were analysed in order to determine the corresponding angles of incidence of greatest sensitivity. For estimating the method sensitivity we used the point sensitivity defined as the Jacobian . The existence of the ambiguities for a method was linked with the Jacobian sign change. We found that Simon's method is practically unambiguous and its sensitivity has a weak dependence on the choice of angles. Also, we found that Avery's method may be ambiguous for certain angles but not for its optimum angles.