Quantitative characterization on multichannel transition emissions originating from ³P₀ and ¹D₂ levels of Pr³⁺ in fluorotellurite glasses

Multichannel transition emissions in Pr³⁺-doped fluorotellurite (4BaF_2-4AlF_3-16BaO-6La₂O_3-70TeO ₂, BABLT) glasses have been quantitatively characterized. Broadband ∼1.48 μm near-infrared (NIR) emission due to ¹D₂ → ¹G₄ transition covering a 1.28-1.68 μm wavelength region possesses a full-width at half-maximum of 120 nm, along with the spontaneous emission probability (A_ij) and maximum stimulated emission cross-section (σ_em) are calculated to be 693 s ^-1 and 8.97 × 10^-21 cm², respectively. Intense visible fluorescence originating from ³P₀ and ¹D₂ levels has been observed and the radiant flux for the visible fluorescence of Pr³⁺ is solved to be 299 μW under commercial blue LED excitation. Quantitative characterization reveals that Pr³⁺-doped BABLT glasses exhibit a quantum yield (QY) as high as 14.9%, which is 3.1% higher than that in Pr³⁺-doped heavy metal germanium tellurite glasses. High QY and broadband ∼1.48 μm emission illustrate great advantages of Pr³⁺-doped BABLT glasses as fibre luminescence sources in photodynamic therapy treatment and gain media for tunable lasers and NIR optical amplifiers.