Optical constants n and κ of various technical and optical glasses at λ = 10.59 μm

The optical constants n (refractive index) and κ (absorption index) of several technical and optical glasses were determined with high accuracy for the CO2 laser wavelength λ = 10.59 μm by angular- and polarization-dependent measurements of reflection at the surface of these glasses. The exact knowledge of n and κ is important for modeling the interaction between CO2 laser radiation and glasses. The investigations were made with low-intense CO2 laser radiation polarized perpendicular as well as parallel to the plane of incidence. The angle of incidence was varied in the range between 0° and 90°. The values of n and κ were determined by means of a fitting procedure between the measured values of the reflectivity and the theoretical curves from Fresnel's formulas. In the case of high absorbing index glasses, the accuracy of this method exceeds ±2% (n) and ±4% (κ), respectively. The measured values show significant differences between typical optical and technical glasses resulting in a linear absorption coe...