High nonlinear optical properties in TeO2-based glasses: A modifier’s influence study from the localized hyperpolarizability approach

Ab initio localized molecular orbital theory (GAMESS program) has been used to evaluate the effects of a second cation on nonlinear optical properties of tellurium oxide based glasses. Calculations were performed on [HnTeO3A3−n]+ (n = 0–3) molecules with alkali cations (A = Li, Na). Results of the calculations on optimized structures show that the effects of the second cation on the nonlinear optical properties are significant and related to the geometric modification of the structural unit. However, the introduction of the second cation induces an increase of both linear polarizability and second hyperpolarizabilty whereas experiments show the opposite, second hyperpolarizabilty is much more affected by the introduction of the second cation. Such calculations have to be performed on bigger size clusters in which the introduction of a second cation implies breaking a Te–O–Te bridge.