Improvements in the determination of extinction coefficients of a thin film using an envelope method

Abstract

The algorithm used in the envelope method has been integrated with a variational method, for accurate determination of the refractive index (n) and extinction coefficient (k) of a weakly absorbing film deposited onto a weakly absorbing thick substrate. The proposed algorithm leads to significant improvement in the degree of accuracy of k values in the medium and weak absorption region down to k~5 × 10−5.