The upconversion luminescence research of Er3+-doped heavy metal oxyfluorosilicate glasses

Abstract

The absorption spectrum, upconversion spectra and Raman spectrum of Er3+-doped heavy metal oxyfluorosilicate glasses have been investigated, and luminescence mechanisms of Er3+ in heavy metal oxyfluorosilicate glasses were analyzed. The results showed that blue, green and red emission centered around 411, 525, 543, and 655 nm, corresponding to the 2H9/2→4I15/2,2H11/2→4I15/2,4S3/2→4I15/2, and4F9/2→4I15/2transitions of Er3+ ions, respectively, were simultaneously observed at room temperature under 975 nm diode laser excitation, and the intensity for blue, green and red emissions increases with increasing Er2O3 concentrations. There are two basic upconversion mechanisms: excited state absorption and energy transfer, and a two-photon upconversion process is assigned to the intense green and red emissions, respectively, while a three-photon process is responsible for weak blue upconversion. Raman spectrum indicates that the lead fluoride in the glass network play an important role in upconvesion fluorescence of Er3+.