Parametrized optical functions of strontium barium niobate crystals in the vacuum ultraviolet spectral range

Abstract

Complex optical function ε(E) = ε1(E) + iε2(E) components parallel ε∥(E) and perpendicular ε⊥(E) to the optic axis are determined in the photon energy range E = 2–10 eV for SrxBa1–xNb2O6 single crystals with the composition parameters x = 0.40, 0.50, 0.61, 0.65, and 0.75. The spectra are obtained from the evaluation of the ellipsometric data using a relevant optical model which takes into account the optical anisotropy of the crystal and surface imperfection of the measured specimens. We report the parameters necessary to construct the optical function for each studied composition. Additionally, the energies of electronic inter-band transitions are obtained from the analysis in terms of standard analytical line shapes.