Efficient second harmonic generation in γ-TeO2 phase

Tellurium dioxide-based glasses and crystalline phases are very promising for use in the technology of non-linear optical materials. The origin of their exceptional nonlinearity can be clearly attributed to the hyperpolarizability of the TeIV atom electronic lone pairs. In recent years our group has developed expertise in both experimental and fundamental research on TeO2-based materials. One of the most significant results was the discovery and the structural characterization of two metastable crysta me polymorphs of TeO2, which we have called delta and gamma. In this paper, we report the characterization of SHG in a powder gamma-TeO2 compound. The gamma-TeO2 SHG signal intensity is then compared to those measured for alpha-TeO2, LiNbO3 and alpha-SiO2 powders.