Comparative study of the spectroscopic properties of Yb3+/Er3+ codoped tellurite glasses modified with R2O (R=Li, Na and K)

Spectroscopic characterization of Yb3+/Er3+ codoped TeO2–R2O–ZnO–Ln2O3 glasses as a function of network modifiers (R=Li, Na and K) has been investigated. The Judd–Ofelt parameters (Ωt), quantum efficiency in near infrared (1.55 μm) and visible up-conversion (546 and 660 nm) and quality factor spectroscopy (χ) were calculated. Three up-conversion emission bands centered at 525, 546 and 660 nm were observed as maxima for glasses containing potassium. The measured lifetime of 4I13/2, 4F9/2 and 4S3/2 from Er3+ and 4F5/2 from Yb3+ levels increased when potassium (K) replaced lithium (Li) and Na. The maximum emission cross-section (ECS) for 4I13/2→4I15/2 transition of Er3+ was calculated to be 1.02×10−20 cm2 for TeO2–Li2O–ZnO–Ln2O3 glasses. The energy transfer efficiency (ET) from Yb3+ to Er3+, (4F5/2)+(4I15/2)→(4F7/2)+(4I13/2), was calculated using the measured lifetimes of Yb3+ with and without the presence of acceptor (Er3+). The maximum calculated ET was 58% for 0.25 mol% of Er3+ and 3 mol% of Yb3+ for TeO2–K2O–ZnO–Ln2O3 glass composition.