Extinction coefficient, k, of the reduced haze analog from UV to NIR retrieved with spectrophotometry on the MgF₂ sample and ellipsometry on the doped Si sample. Top: different spectrophotometric calculations of k from direct/analytical (Swanepoel, Beer-Lambert) and indirect/iterative (point-by-point fitting, Tauc–Lorentz) models. Bottom: measurements of k calculated using different models and different data (ellipsometric and spectrophotometric). The Swanepoel method shown on the bottom panel corresponds to the analytical expression on the top panel (red curve).