Beta-distributed oscillator model as an empirical extension to the Lorentzian oscillator model: physical interpretation of the ${\beta \_{{\rm do}}}$β_do model parameters.

The physical sense of the free parameters of the beta-distributed oscillator (${\beta \_{{\rm do}}}$β_do) dispersion model is discussed. It is shown that the set of six model parameters provides information on central wavenumber, oscillator strength, absorption edge position, asymmetry, as well as homogeneous and inhomogeneous linewidth of a complicated absorption feature. For materials satisfying the Moss rule, the number of independent ${\beta \_{{\rm do}}}$β_do parameters decreases down to five.

Theoretical study of multilayer coatingreflection taking into account third-order optical nonlinearities.

A theoretical approach is presented that allows calculating the reflectance of dielectric multilayer coatings taking third-order optical nonlinearities into account. The description is based on third-order optical susceptibility so that nonlinear refraction and two-photon absorption processes are automatically considered in terms of the real and imaginary parts of the susceptibility. Two model systems are calculated in order to demonstrate the physical validity of the approach: a mirror that is optimized for maximum reflectance at a given wavelength and a given incident intensity and a mirror that provides a rather flat dependence of the reflected intensity on the incident one.

Porosity and optical properties of zirconia films prepared by plasma ion assisted deposition.

The porosity of zirconia films prepared by plasma ion assisted deposition has been investigated by means of optical (spectrophotometric) and nonoptical analytic techniques such as transmission electron microscopy, x-ray reflection, and energy dispersive x-ray spectroscopy. A discrimination between large (open) and small (closed) pores was achieved by means of measurement of the thermal and vacuum-to-air shift. Depending on the level of plasma assistance during film preparation, the porosity was found to vary between 30 vol.

Investigation of the refractive index repeatability for tantalum pentoxide coatings, prepared by physical vapor film deposition techniques.

Random effects in the repeatability of refractive index and absorption edge position of tantalum pentoxide layers prepared by plasma-ion-assisted electron-beam evaporation, ion beam sputtering, and magnetron sputtering are investigated and quantified. Standard deviations in refractive index between 4*10 and 4*10 have been obtained. Here, lowest standard deviations in refractive index close to our detection threshold could be achieved by both ion beam sputtering and plasma-ion-assisted deposition.

Analytical elimination of substrate backside reflections from reflectance measurements.

An analytical approach to eliminate substrate backside reflections from measured reflectance of an unknown optical coating has been deducted. Thereby, measured transmittance, reflectance, and backside reflectance of the coating and transmittance and reflectance of the uncoated substrate at the desired angle of incidence and polarization state are required as input data. In the underlying theory, layer and substrate materials may be absorbing.