Optical properties of soda lime float glass from 3 mm to 148 nm (0.41 meV to 8.38 eV) by spectroscopic ellipsometry

Abstract

The optical properties of soda lime float glass (SLG) have been characterized over a wide spectral range from 0.41 meV to 8.38 eV using spectroscopic ellipsometry and from 0.74 to 4.80 eV by unpolarized transmittance spectroscopy to retain sensitivity to the onset of high photon energy absorption. In all, the raw measured spectra are collected using four separate instruments, each covering different portions of the full measured spectrum. The glass is modeled as two separate surface layers on either side of a bulk SLG slab to account for variations in surface properties arising from the float glass fabrication process. The measurements are sensitive to the thicknesses of each of these layers and to the optical properties of each, which are reported as both the complex dielectric function (ε = ε1 + iε2) and complex index of refraction (N = n + ik). Despite the measurements being collected on multiple instruments, the optical properties of each layer are represented as single, continuous parametric functions.