Upconversion photoluminescence properties of Ho3+/Yb3+ co-doped YNbO4 powder

Upconversion luminescence characteristic about YNbO4 powder material doped with Ho3+ and Yb3+ ions is reported. Ho3+/Yb3+ co-doped YNbO4 powder material is prepared through solid-state reaction, absorption spectrum of prepared sample is measured and spectral characteristic is calculated through Judd-Ofelt (J-O) theory. Emission spectrum of prepared sample excited under 980 nm laser diode (LD) is obtained, and results indicate that there are three groups of upconversion emission peaks located at 540 nm and 548 nm, 642 nm and 663 nm, 758 nm, respectively, which correspond to level transitions from 5F4 to 5I8, from 5F5 to 5I8, from 5F5 to 5I7 of Ho3+ ions. Curve fitting of relationship between upconversion luminescence intensity and working current of exciting LD is done, and the fitting results prove that this up-conversion luminescence are all two-photon absorption procedure.