Upconversion mechanisms in Tm3+ doped lead fluoroindogallate glasses

A spectroscopic study of Tm3+ doped lead fluoroindogallare was performed here, The samples were prepared by fusion in a dry box under a nitrogen atmosphere. Their compositions are 30PbF(2)-20GaF(3)-15InF(3)-15ZnF(2)-(20 - x)CaF2-xTmF(3) (with x = 0.1, 0.25. 0.5, 1.0, 2.0 and 3.0 mol%). Pumping with 660 or 649 nm resulted in three upconverted emissions at 360 nm (D-1(2) --> H-3(6)), 450 nm (D-1(2) --> F-3(4)) and 470 nm ((1)G(4) --> H-3(6)). The relative intensity between the 470-nm emission and the others increased as the Tm3+ concentration increases. The observed features were satisfactorily explained by cross-relaxation mechanisms involved in the population of the D-1(2). (1)G(4) and F-3(4) levels. (C) 2000 Elsevier Science B.V. All rights reserved.