Refractive index dispersion of germanium-arsenic-selenide (GeAsSe) glasses

Abstract

This work reports trends for the electronic band edge, the transmission window, infrared active structural signatures, and ultra-high measurement density of the real refractive index from their electronic band edge out to 14 µm for the GexAsySe(100-x-y) glass family where Se(100-x-y)>Se60. This region of the ternary glass family has electronic band edges reported from 1.28 eV to 1.69 eV, optical shortwave cutoffs from 720 nm to 920 nm. Completing the transmission window is the longwave cutoff caused from the measured two-phonon infrared active structural signatures with a reported range from 15.85 µm to 18.42 µm. The refractive index dispersion is calculated with over 100 direct measured data points and are fit using a 3-term 6-variable Sellmeier equation with a R2 better than 0.99999999.