Fc. Guinhos et al., Compositional dependence of up-conversion process in Tm3+-Yb3+ codoped oxyfluoride glasses and glass-ceramics, J ALLOY COM, 323, 2001, pp. 358-361
Up-conversion of infrared radiation to the visible and ultraviolet regions
in PbF2-GeO2-Al2O3 -Tm2O3-Yb2O3 oxyfluoride glasses and glass ceramics was
obtained, exciting at 1.0 mum with a diode laser at room temperature. Trans
parent films and microspheres were prepared by a modified spin-coating tech
nique. The effect of host composition on the up-conversion luminescence was
studied in order to improve the ultraviolet radiation generation. In the g
lass samples, the Tm3+ blue (4786 Angstrom) and red (6500 Angstrom) visible
emissions got more intense as the PbF2 content was increased. The main Tm3
+ blue emission (4786 Angstrom,(1)G(4)--> H-3(6)), results from a three-pho
ton process. A second blue emission (4500 Angstrom, D-1(2)--> F-3(4)), foll
owed by a UV emission (3650 and 3850 Angstrom, D-1(4)--> H-3(6)) was observ
ed in the (2PbF(2)/GeO2) glass ceramics, in a narrow range of Al2O3 concent
ration. The D-1(2) level of the Tm3+ ions is populated by a fourth photon f
rom the cross-relaxation process given by (F-3(4), (1)G(4))-->(H-3(6),D-1(2
)). (C) 2001 Elsevier Science B.V. All rights reserved.