Structural engineering and optical nonlinearities based on Nb2O5 effects in tellurite-zinc-lanthanum glasses

Alejos-Hendenmann J.I.; Chacaliaza-Ricaldi J.; Marucci N.B.; Ferreira M.J.; Pimenta A.C.S.; Ramos-Guivar J.A.; Mendonça C.R.; Marega E., Jr.; Rivera V.A.G. · Journal of Alloys and Compounds (2026) · DOI: 10.1016/j.jallcom.2026.191394

Resumen

Modifying the local structure of tellurite-zinc-lanthanum glasses through Nb2O5 incorporation provides a direct route to tune their structural, thermal, and optical response to open new technological applications. However, the extent to which Nb2O5 simultaneously modifies network connectivity, glass stability, and third-order nonlinear behavior remains insufficiently understood. In this work, a series of (85–x)TeO2–10ZnO–5La2O3–xNb2O5 (x = 0–15 mol%) glasses were prepared by the melt-quenching technique. UV–Vis analysis revealed a red shift of the absorption edge, accompanied by reductions in the direct and indirect optical bandgaps and in the Urbach energy, indicating a more polarizable and electronically homogeneous glass network when the Nb2O5 content increases. In parallel, the glass transition temperature increased linearly with Nb2O5 content, evidencing improved thermal rigidity. Raman spectroscopy showed that Nb2O5 acts mainly as an intermediate/network-forming oxide, promoting [NbO6] structural units and enhancing network connectivity. Z-scan measurements demonstrated that these structural modifications preserve a positive third-order nonlinear refractive response, with n2 values on the order of 10−19 m2/W. Furthermore, the linear-absorption figure-of-merit revealed spectral regions compatible with Fabry–Perot filters, Mach–Zehnder interferometers, and nonlinear directional couplers. These findings identify Nb2O5 as a key compositional handle for coupling structural reorganization with bandgap control and nonlinear optical response in tellurite-zinc-lanthanum glasses, opening new opportunities for the design of photonic glass platforms.

Instituciones: Universidad Nacional Mayor de San Marcos