X-ray absorption spectroscopy of doped and undoped multilayer (SiO2/Ta2O5) coatings on fused silica (SiO2) substrates

We report results from our use of X-ray absorption spectroscopy to obtain chemical and structural features of dielectric multilayer (SiO2/Ta2O5) mirror coatings. For the ion beam sputtered multilayers studied here, we obtained Ti/Ta atom ratios in the range of 0.07–1.01. Relatively minor amounts Fe and Cr appear in the spectra at a constant atom ratio, Cr/Fe, of 0.41±8.31%. All the samples show maxima in the radial distribution functions between 1 and 2 Å, assigned to Ta–O bonds.