Intense ultraviolet upconversion luminescence from Yb3+ and Tm3+ codoped amorphous fluoride particles synthesized by pulsed laser ablation

Zn0.3Al0.25Pb0.3Li0.098Yb0.1Tm0.002F2.354 amorphous fluoride particles were prepared by pulsed laser ablation. Under a 978-nm laser diode excitation, intense ultraviolet and blue upconversion emissions were observed in the particles. Intensity dependence of the upconversion emissions on the pump power was measured. The results show that the population of the states I-1(6), D-1(2) and (1)G(4) may come from a five-photon, four-photon and three-photon energy transfer upconversion process. In addition, ultraviolet (I-1(6) --> F-3(4) transition) and blue (D-1(2) --> F-3(4) transition) upconversion stimulated emissions were observed in the particles. (C) 2004 Elsevier B.V. All rights reserved.