Up-conversion properties in KGd2F7:Yb3+/Er3+

Infrared to visible up-conversion emissions in Yb3+–Er3+ co-doped KGd2F7 samples excited at 980 nm are presented in this paper. Green (2H11/2,4S3/2→4I15/2), red (4F9/2→4I15/2) and violet (2H9/2→4I15/2) emissions are observed under low pumping power, and the green emission is dominant. The dependences of these emissions as function of the pumping power intensities and the doped rare-earth ion concentrations are described. The results indicate that the green and red emission of Er3+ ion result from two-photon excitation processes, and the violet emission of Er3+ ion from three-photon processes. The most efficient composition for green emission is 2–4 mol% Er3+ and 10–20 mol% Yb3+ in synthesized samples. The mechanisms for explaining these up-conversion properties have been provided.