Pure TeO2 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 °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 ρ (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 E_g(3.69 → 3.72 eV) and Abbe number ν_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.

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