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

Multichannel transition emissions in Pr3+-doped fluorotellurite (4BaF2–4AlF3–16BaO–6La2O3–70TeO2, 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 (Aij) and maximum stimulated emission cross-section (σem) 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. (paper)