Persistent luminescence upconversion for Er₂O₃ under 975 nm excitation in vacuum

The 975 nm excited emission of Er₂O₃ in the infrared (IR) and visible spectral regions at powers below the threshold for broadband white light generation has been investigated. In this regime the log(emission intensity) vs log(power) plots for emission at 660 nm and 154 nm exhibit slopes for the sample in air (vacuum) of ~1 (~5) and ~1 (~2), respectively and the excitation mechanisms are discussed. The build-up of the emission is on the timescale of seconds and the excitation and decay transients have been recorded and analyzed for various excitation powers. The decay of the IR and visible emission each follow biexponential processes on a second timescale. The duration and kinetics of the emission decay are characteristic of persistent luminescence. Copyright © 2015 Elsevier B.V.