Optimizing Nd/Er ratio for enhancement of broadband near-infrared emission and energy transfer in the Er3 +–Nd3 + co-doped transparent silicate glass-ceramics

• NIR emission of Er–Nd has significantly enhanced after heat treatment changing times.
• Broadband NIR of Er–Nd with an FWHM extending from 1250 to 1700 nm could be 340 nm.
• NIR emission of Er–Nd, which covered the whole O, E, S, C, L and U bands was observed.
• NIR emission bands at 1065 and 1546 nm are best for Nd/Er ratio of 2.5.
• Energy transfer processes between the Nd3 + and Er3 + ions were also discussed.

The optimizing Nd/Er ratio for enhancement of broadband near-infrared (NIR) emissions in the Er3 +–Nd3 + co-doped SiO2–AlF3–BaF2–TiO2–CaCO3 (SABTC) transparent silicate glass-ceramics containing BaF2 nanocrystals under 808 nm excitation was investigated. The broadband NIR emission bands from 850 to 1700 nm, which covered the whole O, E, S, C, L and U bands were observed in the Er3 +–Nd3 + co-doped glass-ceramics samples, as a result of the overlap of Nd3 +-doped emission band centered at 1342 nm and the emission from 4I13/2 → 4I15/2 transition of Er3 + band centered at 1546 nm. The NIR emission intensity of Er3 +–Nd3 + co-doped bands centered at 895, 1065, 1342 and 1546 nm, becomes stronger with varied depending on the mixing ratio of Nd3 + and Er3 + ions, and the full width at half-maximum (FWHM) extending from 1250 to 1700 nm could be 340 nm. Most NIR emission bands at 1065 and 1546 nm are observed for the SABTC-1.0N0.4E glass-ceramics sample, corresponding to Nd/Er ratio of 2.5. At the same time, the energy transfer processes between the Nd3 + and Er3 + ions were also discussed.