Pure TeO 2 glass: Influence of synthesis conditions on linear and non-linear optical, magneto-optical and structural properties

The first systematic study of linear and non-linear optical, magneto-optical and structural properties of pure TeO2 glass is presented with regard to different synthesis and material processing conditions. Prepared glasses were synthesized by the intermittent quenching from 900 degrees C in platinum or alumina crucibles and characterized prior to and after optical polishing. The position of the long-wavelength/phonon absorption edge was investigated using various optical models and experimentally obtained data of refractive index and Verdet constants were used for the estimation of magneto-optical anomaly parameter. During synthesis in alumina crucible, up to about 11 wt.% of Al2O3 incorporates into the glass (verified by EDS/XRF and Raman/FTIR spectroscopy) partially transforming the original pure TeO2 glass backbone structure composed of [TeO4] trigonal bipyramids to [TeO3+1] and [TeO3] structural units with the expected integration of Al into Te-O-Al bridges. The presence of Al2O3 results in lowered density rho (5.60 -> 4.72 g cm-3), refractive index n1550 (2.086 -> 1.927) and Verdet constant V632 (36.3 -> 21.9 rad T- 1 m- 1) and in increased optical-band-gap energy Eg (3.69 -> 3.72 eV) and Abbe number nu D (19.9 -> 26.9) compared to pure TeO2 glass prepared in platinum crucible. A dataset of the obtained complex optical parameters (refractive index and extinction coefficient) in the wide spectral range of 193 11000 nm is included in the supplementary part.