Optical transitions of Ho3+ in oxyfluoride glasses and upconversion luminescence of Ho3+/Yb3+-codoped oxyfluoride glasses

•Ho3+-singly doped and Ho3+/Yb3+-codoped SiO2–BaF2–ZnF2 glasses were prepared.•Judd–Ofelt analysis indicated the glass structure changed with change of glass composition.•The intensity of upconversion luminescence decreased with increasing ZnF2 content.

Optical properties of Ho3+-doped SiO2–BaF2–ZnF2 glasses have been investigated on the basis of the Judd–Ofelt theory. Judd–Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Ho3+/Yb3+-codoped SiO2–BaF2–ZnF2 glasses under 980 nm excitation. The effects of composition, concentration of the doping ions, and excitation pump power on the upconversion emissions were also systematically studied.

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