Enhancement of ultraviolet upconversion in Yb3+ and Tm3+ codoped amorphous fluoride film prepared by pulsed laser deposition

Zn0.3Al0.25Pb0.3Li0.098Yb0.1Tm0.002F2.354 amorphous fluoride film was prepared by pulsed laser deposition. Ultraviolet and blue up-conversion emissions were observed under infrared excitation at 978 nm. In comparison with the upconversion of the target, the ultraviolet emissions are enhanced greatly. The enhancement is attributed to a decrease of the Judd-Ofelt parameter Omega(2) induced by pulsed laser deposition, which precludes the transition rate from F-3(2) to F-3(4) and enhances the energy transfer process and populates the D-1(2) level: F-3(2)-->H-3(6) (Tm3+):H-3(4)-->D-1(2) (Tm3+). (C) 2003 American Institute of Physics.