Ytterbium-induced energy-transfer upconversion enhancement in Nd 3+/Pr 3+-codoped PbGeO 3–PbF 2–CdF 2 glass excited at 810 nm

Abstract

The effect of ytterbium ions upon energy transfer (ET) excited upconversion emission in Nd 3+/Pr 3+-codoped PbGeO 3–PbF 2–CdF 2 glass under 810 nm diode laser excitation is investigated. The results revealed that the presence of Yb 3+ ions in the Nd 3+/Pr 3+-doped sample yields a fourfold enhancement in the visible and near infrared upconversion luminescence. The dependence of the upconversion process upon the excitation power, Nd 3+, and Yb 3+ concentrations is examined. The results indicated that ytterbium plays a major role in the ET upconversion process by bridging the 810 nm neodymium excitation to praseodymium ions. The population of the Pr 3+ ions 3P 0 emitting level was accomplished through a multi-ion interaction involving ground-state and excited-state absorption of pump photons at 810 nm by the Nd 3+ followed by successive ET involving the Nd 3+–Yb 3+ and Yb 3+–Pr 3+ pairs. There is also direct ET Nd 3+–Pr 3+.