Role of Yb3+ions in the IR to visible upconversion of Er3+ions in LTT glasses

Abstract

ABSTRACT In order to develop efficient visible upconversion lasers and optical fiber amplifiers, the detailed spectroscopic properties of singly doped Er 3+ and codoped Er-Yb ions in lead tungsten tellurite (LTT) glasses have been investigated. The glasses were prepared by the conventional melt quenching technique. Absorption, visible upconversion spectra and NIR emission spectra we re recorded as a function of Yb 3+ ions concentrations. Judd-Ofelt (J-O) analysis has been performed for the spectral intensities of Er 3+ and Er -Yb absorption bands. Spontaneous emission probabilities (A R ), radiative lifetimes (2 R ) and branching ratios ( R ) were calculated by using the phenomenological Judd-Ofelt intensity parameters. Three strong upconversion emission bands centered at 526, 551 and 665 nm were observed under 980nm excitation, due to the energy transfer process from Yb 3+ to Er 3+ ions. The green emissions centered at 526 and 551 nm and the red emission at 665 nm are attributed to