Luminescence quantum efficiency at 1.5 μm of Er3+-doped tellurite glass determined by thermal lens spectroscopy

Erbium doped tellurite glasses (TeO₂ + Li₂O + TiO₂) were prepared by conventional melt-quenching method to study the influence of the Er³⁺ concentration on the luminescence quantum efficiency (η) at 1.5 μm. Absorption and luminescence data were used to characterize the samples, and the η parameter was measured using the well-known thermal lens spectroscopy. For low Er³⁺ concentration, the measured values are around 76%, and the concentration behavior of η shows Er–Er and Er–OH⁻ interactions, which agreed with the measured lifetime values.