Multicolor frequency upconversion luminescence in Eu3+/Tb3+/Yb3+-codoped fluorogermanate glass excited at 980Â nm

Glasses80GeO3:10PbF2:10CdF2 triply-doped with europium, terbium, and ytterbium phosphors were synthesized and the energy up-conversion luminescence emission properties investigated as a function of NIR excitation power, rare-earth ions content combination, and glass phosphor composition. Multicolor visible luminescence with main emissions peaked around 490, 545, 590, 610, 650, and 700 nm was observed when samples were excited by a diode laser at 980 nm. The up-conversion excitation mechanism for both Eu3+, and Tb3+ excited-state emitting levels was achieved via phonon-assisted cooperative energy-transfer from pairs of excited Yb3+ ions. White-light emission with CIE-1931 coordinates in the region of low color correlated temperature was obtained for appropriate combination of rare-earth ions content.