Sensitizing effect of Yb3+ ions on 1.53 µm broadband and 548nm upconversion green emissions of Er3+-doped TeO2–WO3–GeO2 glasses

Abstract

The Er3+-doped transparent glasses were the significant materials to design solid state visible lasers, near infrared lasers, upconverters, sensors and fiber amplifiers. The effect of Yb3+ sensitization on 1.53 µm broadband and 548 nm upconversion green emissions in TeO2–WO3–GeO2–ErF3–YbF3 (TWGErYb) glasses were studied. They were characterized through structural, optical absorption, near infrared and upconversion studies. The Judd-Ofelt theory was adopted to estimate several spectroscopic and radiative parameters. The laser characteristic parameters such as stimulated emission cross sections, gain band widths, figure of merit and quantum efficiencies were evaluated. Conveying the energy from Yb3+ to Er3+ ions and the reasons for non-radiative losses were highlighted. The quenching in luminescence of 1.53 µm broadband, the 548 nm upconversion green emissions and the enhanced decay time values due to self-absorption were studied. The fitting of decay curves of Er3+: 4I13/2 and Er3+: 4S3/2 emission states at higher Yb3+concentrations (≥1.5 mol%) to Inokuti-Hirayama model were discussed. The TWGErYbx glasses containing 0.5Er3+/2.5Yb3+ show proficiency to design 548 nm green solid state lasers and 1.53 µm broadband fiber lasers.