<title>MIR/NIR/VIS spectrophotometric investigation of absorbing thin-film materials based on error function minimization by the method of conjugated gradients</title>

Abstract

A flexible numerical procedure for the calculation of thin film optical constants from specular transmittance and reflectance data is presented. The method is based on the minimization of an error function, which may be adapted to the specifics of the optical behavior of the given sample (or set of samples), and the given wavenumber region. The flexibility in choosing an appropriate form of the error function minimized, in combination with the powerful minimization method of conjugated gradients, allowed us to investigate the optical constants of very different types of novel thin film materials with a complicated absorption behavior. In particular, the results concerning the investigation of single- and two-layer-systems based on the following optical thin film materials are presented: amorphous silicon, phthalocyanine layers, hydrogenated amorphous carbon, and as-deposited (rough) CVD diamond layers.