Optical constants of absorbing thin solid films on a substrate

The optical constants nf and kf of an absorbing thin solid film, deposited on a transparent or a slightly absorbing substrate, depend in a complex way on measurable quantities such as the transmittance T and the air-incident and substrate-incident reflectances R and R′. Simple analytical formulas, which minimize propagation of experimental errors, are derived for determining ks of the substrate and kf and nf of the film. The formulas are applied to Te alloy films of varying thickness deposited on glass substrates.