Second Harmonic Generation induced by optical poling in new TeO2-Tl2O-ZnO glasses

Article abstract of DOI:10.1016/j.materresbull.2010.01.024

New tellurite glasses with a large glass forming domain were elaborated within the TeO₂-Tl₂O-ZnO ternary system. The evolution of the glass transition (T_g) and onset crystallization (T₀) temperatures for such tellurite glasses was studied, in particular, as a function of the Tl₂O addition. A decrease of both T_g and T₀ temperatures was observed; the former being more affected. Structural modifications induced by the addition of the modifiers were studied by Raman spectroscopy. For a fixed ZnO concentration, the increase in the Tl₂O content leads to a destruction of the glass framework, characterized by the transformation of TeO₄ disphenoids into isolated TeO₃^2- trigonal pyramid-like ortho-groups. For a fixed Tl₂O concentration, the ZnO addition induces similar effects on the glass structure. The optical transmission of the ((80 - x)TeO₂-xTl₂O-20ZnO) (x = 10, 20 and 30 mol%) glasses was measured in the 300-2000 nm range. Their good transparency was evidenced and a clear reduction of the optical band-gap was noticed with the increase in the Tl₂O content. Finally, Second Harmonic Generation was unambiguously detected for each glass composition. The second order non-linearity amplitude is found to be increasing as a function of the Tl₂O concentration, in the tested range.