Theoretical studies of the sensitivities of non-normal incidence methods for measuring the optical constants of thin films

The sensitivity studies for methods of measuring n, k and d /λ of a thin film by optical methods have been extended to cases of non-normal incidence. The results for each pair of parameters are exhibited in the form of sensitivity diagrams. The diagrams for ( T p , T s ) and ( R p , R s ) at θ = 45°, 60° and 75° show overall high sensitivity over the region 0 < n < 3, 0 < k < 3, 0 < d /λ < 0·02. For other combinations the regions of high sensitivity were arranged symmetrically about the line n = k and showed sensitivity in only two of the three directions. For all combinations except ( R p , R s ) the sensitive region decreased with d /λ. No combination was found having high sensitivity in the region n > 3, k > 3.