Precise optical constants of Ge and GeO2 from 0.5 to 6.6 eV

Germanium-based photonics or photovoltaics applications require precise knowledge of the optical constants (refractive index, absorption coefficient, dielectric function) for Ge and GeO
₂
over a broad spectral range. Unfortunately, we don't know as much about these as for Si and SiO
₂
. We therefore apply the same technique to Ge (spectroscopic ellipsometry with multi-sample analysis), which was used to determine the so-called “Woollam Silicon” optical constants.