Emissions properties of Ho3+: 5I7 → 5I8 transition sensitized by Er3+ and Yb3+ in fluorophosphate glasses

Emission properties of Ho3+ at 2.0 μm and the energy transfer mechanism between Yb3+, Er3+ and Ho3+ ions in fluorophosphate glasses are investigated. The measured emission spectra show that the 5I7 → 5I8 transition of Ho3+ upon 980 nm laser diode excitation is strong. Judd–Ofelt intensity parameters (Ωλ, λ = 2, 4, 6), spontaneous transition probability (Arad), radiative lifetime (τr), absorption cross section (σa), stimulated emission cross section (σe) and FWHM × σepeak for the transition of Ho3+: 5I7 → 5I8 are calculated and discussed. The obtained results show that the present Yb3+/Er3+/Ho3+ triply-doped fluorophosphate glass can be identified to be a promising material at 2.0 μm emission.