Photoluminescence and upconversion emission of Er3+/Yb3+ codoped tungsten tellurite oxyfluoride glasses

Abstract

Abstract The codoped YbF3 / ErF3 with the optimum composition of TeO2-Li2O-WO3 (TWLEYF) oxyfluoride glasses in which minimizing the fluoride contain were synthesized by melt quenching technique. UV-Vis absorption spectrum of the sample was measured for identification of the absorption levels of Er3+/Yb3+ ions in the glass. Photoluminescence of glass sample produced the intense broad blue emission of Er3+(2mol%) under UV excitation at 380nm. The intense green upconversion at 535nm and weak green at 550nm under 800nm excitation has been measured. Also, a weak blue and red upconversion emission band of Er3+ ions was observed. Further for 2 mol% of YbF3 in TWLEYF samples is attributed to enhance 535nm emission due to energy-transfer process while the red emission is based on non-resonant energy transfer performs. At room temperature green fluorescence decay times of 4S11/2 level of Er3+ ions under 488nm pulse excitation duration at rate < 10ns have been measured. Moreover, 530nm upconversion emission process of tungsten tellurite oxyfluoride glasses were discussed which would be useful for optical devices.