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

Abstract

Zn 0.3 Al 0.25 Pb 0.3 Li 0.098 Yb 0.1 Tm 0.002 F 2.354 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 Ω2 induced by pulsed laser deposition, which precludes the transition rate from 3F2 to 3F4 and enhances the energy transfer process and populates the 1D2 level: 3F2→3H6(Tm3+):3H4→1D2(Tm3+).