Infrared-to-ultraviolet up-conversion luminescence from AlF3: 0.2%Tm3+, 10%Yb3+ particles prepared by pulsed laser ablation

AlF3: 0.2%Tm3+, 10%Yb3+ particles were prepared by pulsed laser ablation (PLA). Under a 978 nm laser diode excitation, intense ultraviolet and weak blue up-conversion emissions were observed in the AlF3: 0.2%Tm3+, 10%Yb3+ particles. Intensity dependence of the up-conversion emissions on the pump power was measured. The results show that the population of the states 1I6, 1D2 and 1G4 may come from a five-photon, four-photon and three-photon energy transfer up-conversion process.