Study on 2.0 μm fluorescence of Ho-doped water-free fluorotellurite glasses

• Ho-TZNF60 glasses were made by specially-designed PCDH technique.
• Mid-IR emission spectra were deeply probed experimentally.
• The longest fluorescence lifetime at 2.04 μm is presented in Ho-TZNF60 glass.
• 1.00Ho-TZNF60 glass is ideal material to develop Mid-IR fiber lasers.

Ho3+-doped water-free fluorotellurite glasses with composition of 60TeO2–30ZnF2–10NaF (mol%, TZNF60) were made by using specially-designed physical and chemical dehydration technique. 2.04 μm fluorescence (Ho3+: 5I7 → 5I8) was observed experimentally and presented in this paper: A broad bandwidth of ∼149 nm, large simulated emission cross-section of 7.2 × 10−21 cm2, and the longest reported fluorescence lifetime of ∼10 ms among all the reported Ho3+-doped oxide glasses. Thanks to the absence of OH groups and low phonon energy with the addition fluorides into tellurite oxide glasses, 1.00Ho-TZNF60 glass demonstrates the maximum figure of merit (σem × τf) of 7.13 × 10−27 m2 s, thus regarded as a promising optical material for the development of 2.0 μm fiber lasers.