Spectroscopic study of Dy and Dy/Yb ions co-doped in barium fluoroborate glass

Dy³⁺ and Dy³⁺/Yb³⁺ co-doped barium fluoroborate glasses have been synthesized and their luminescence properties have been monitored under UV (355 nm) and NIR (976 nm) excitations, respectively. Absorption spectra of the two samples were recorded and Judd–Ofelt intensity parameters and other radiative parameters were calculated and compared. Dy³⁺ doped sample yields strong yellowish white emission under 355 nm excitation. No emission is observed with 976 nm excitation. The Dy³⁺/Yb³⁺ ions co-doped sample on the other hand gives weak upconversion emission in blue, yellow and red regions on 976 nm excitation via energy transfer process from Yb³⁺ to Dy³⁺ ions from other level. An involvement of three photons has been noted for these emissions. Decay curve for different transitions of these samples have also been recorded and the lifetime of the corresponding levels involved are calculated.