Infrared to visible upconversion in Er 3+-doped lead oxyfluorosilicate glasses

Abstract

The upconversion properties and mechanism of Er 3+ ions have been studied for lead oxyfluorosilicate glasses containing Er 2O 3 concentrations from 0.2 to 2 mol%. Under 975 nm excitation, four emission bands centered at 411, 525, 543, and 655 nm corresponding to the 2H 9/2→ 4I 15/2, 2H 11/2→ 4I 15/2, 4S 3/2→ 4I 15/2, and 4F 9/2→ 4I 15/2 transitions of Er 3+ ions, respectively, were simultaneously observed at room temperature. The bright green and red emissions are due to a two-photon upconversion process while the weak blue emission is determined by a three-photon upconversion process. Raman spectrum indicates that fluoride ions in the formation of glass network have important influence on upconversion luminescence of Er 3+ in lead oxyfluorosilicate glasses. The intense upconversion luminescence of Er 3+-doped lead oxyfluorosilicate glasses may be a potentially useful material for developing upconversion optical devices.